Develop Bugs

[Solved] Your sim card does not allow a connection to this network

Solved for me @ post #5 http://forum.xda-developers.com/showpost.php?p=10865272&postcount=5
I've searched, read, and called my mobile provider (3 UK) to no avail, so I'm starting a fresh thread on this issue.
Relevant details:
Nokia E65 + 3 PAYG sim = ok
HTC Desire unlocked (from T-Mobile) + 3 PAYG sim = "Your sim card does not allow a connection to this network"
HTC Desire above, + O2 + Virgin sim = ok
From what I've learned this has nothing to do with Android os, ROM or RUU etc., and is purely a setting/sim/connection/whatever problem. Or is it?
I bought an unlocked T-mob-branded Desire which works with o2/virgin sims, but selecting my 3 network results in the "Your sim card does not allow a connection to this network" message - yet same sim is fine in my Nokia. Which I cannot work out as that implies it's a combination of phone+network, surely?
When I first got the phone, unpacked it, 3 sim in, it worked, so I rooted w. Unrevoked it and it still worked, then I Nandroid-backup'd (which I still have), then I tried I think Cyan rom 6ish, and Oxygen 2 rc6 with a Goldcard in place [goldcard has nothing to do with sim/connection, just flashing, correct?], no service/not allowed on network; same with oxygen rom. So I nandroided-restored and still no luck.
I unrooted by RUU-ing with:
RUU_Bravo_Froyo_HTC_WWE_2.29.405.5_Radio_32.49.00. 32U_5.11.05.27_release_signed.exe
(I'm on 3 so tried RUU_Bravo_H3G_UK_1.22.771.1_Radio_32.36.00.28U_4.06.00.
02_2_release_127568_signed.exe to get a '3-rom'd phone' but I can't downgrade-which is fine by me)
so I'm back to Froyo 2.2 stock/whatever it's called, and no luck still. I mention this as I'm sure all this rom-ing has absolutely nothing to do with it but would like to be clear.
Has anyone any idea what causes this occur - not connecting that is - would 'disconnecting from network, romming, loading a new rom w/ sim, connecting and getting maybe kicked off' be the case? Or is this certainly a problem with the sim and this phone and the network; or can somehow a phone be unlocked only on certain rom and not transfer (certain this is not correct) to another - unbranding via goldcard + RUU 2.29..... has been done numerous times by people yet I seem to get this problem.
Long post, but if someone can definitely help it would be greatly appreciated - while comments like 'have you rebooted' are nice, yes, I have many many times, wipes settings, factory restored data, input apn settings, *#4636#*#* doesn't show anything I can really find of use (I tried selecting GSM only, WCDAM only, neither work) and I've tried manually/automatically connecting to network but am plagued with my "Your sim card does not allow a connection to this network" message. Which ultimately makes my £300 phone as much use as an iPhone 4 being held wrong.
I cannot understand how my sim worked before on the same phone, but now after tinkering (nothing of which I think can effect this problem) it's not working again. Apart from my old Nokia.

goto *#*#4636#*#* and post your signal strength (in dbm) and LAC and CID values. It will also be good if you could attach output of logcat -b radio.
This is a well known problem with a no known answer.

Is the number stored correctly - i.e. it hasn't lost the '+' from a number starting 44?
Sent from my HTC Desire using XDA App

I had the same problem two weeks ago when I returned from my holidays. I put in my 3 UK sim and it refused to connect with that same error. Sim worked perfectly in other phones.
Finally 3 UK advised me to do a factory reset on my from the Settings->Storage menu which resolved the issue. You seem to have done a full restore from a RUU which probably should be equal to doing a factory reset. But it's probably worth while doing it anyway in case the issue was with the /data or cache partition which for some reason might not have been cleaned by the RUU.

Well, I *think* I've fixed this (for me at least) - just waited a few days and tested to make sure it wasn't a 'ymmv' quick quip fix.
Basically, I'm on 3 - 3G only - and phone was set to 'WCDMA (3G) preferred' - with low signal/reception (-113dbm) it seemingly tries to get the 2G signals around (Orange-whom 3 piggyback[ed] on in low 3G areas; and O2) while changing to 'WCDMA Only' forced it to only try 3G networks - 3.
So, try this:
Key in, but don't 'call': *#*#4636#*#*
Select Phone Information
Near bottom, Set preferred network type to: WCDMA Only
Fixed it for me instantly. Three mobile UK still has -111dbm as it's best reception here but now at least I can connect to it
Let me know if this fixes it for you (clearly, if you're on a 2G-only network selecting GSM only (2G) may work).

checked your IMEI matches from *#06# and the back of the phone?

Yep, IMEIs match. I think it's (been) purely a network choice/connection issue, at least for me.

hi all. I was as usual using my xperia j but 3g signal was low so I installed signal booster app and after boosting signal the app asked with a popup window to enter network unlock password. I without thinking anything entered 12345 and after this it said wrong network password. since this happened I am getting error on Xperia J (st26i) that your sim doesn't allow connection to this network. I tried with many sims but no signal. It always shows all networks when search for network manually. But gives that above mentioned error when trying to connect to any searched network. I checked if my imei is blacklisted but there's no problem about imei. its clean. I flashed stock rom, custom rom but nothing helped. how to solve this strange error.

Mehul (nope imei does not match)
lothaen said:
checked your imei matches from *#06# and the back of the phone?
Click to expand...
Click to collapse
no my imei is different, now what should i do

I posted that six years ago. I have no idea what my thought process was tbh

[Q] Your SIM card does not allow a connection to this network

(reposted from G1 SIM card does not allow connection thread)
When I went to bed on April 20th, my factory unlocked rooted HTC Desire CM7 (final) handset was working perfectly. When I woke up the following morning, I had "Emergency Calls Only" and "Your Sim Card Does Not Allow A Connection To This Network". While in this condition, I can sometimes get a 3g data connection and WiFi, GPS and the rest of the phone works well. The connection status bar shows 3-4 bars of signal strength for my service provider.
I have:
o Contacted my service provider (O2) and my IMEI is not blocked
o Tried every suggestion in every thread on the topic here and anywhere else Google sent me including toggling flight mode
o Tried the SIM in other phones - works perfectly
o Tried other SIMs in it - same error persists with another O2 SIM and a 3 SIM. The phone correctly identified that the 3 SIM was alien to it before going ahead to use it, showing that the phone IS mounting SIMs
o Rebooted.
o Factory reset.
o Removed battery for 1hr. Rebooted.
o Factory reset and re-installed a Sense Froyo Stock ROM
o Updated the Radio driver with 32.54.00.32U_5.14.05.17.zip
o At each stage tried combinations of disabled WiFi and 3g and auto-update
The nitty gritty from the *#*#4636#*#* Phone information screen contains the following (with 4 bars of signal):
IMEI: (correct code - matches the one behind the battery)
Phone Number: (my number - as defined by the SIM)
...
Location: LAC = unknown CID = unknown
Neighbouring CID = unknown
Roaming: Nor roaming
GSM service: Emergency calls only
GPRS service: Disconnected
Network type: unknown
...
Radio resets: 0
Data attempts: 0
Data successes: 0
GSM disconnect: ========DATA=======
State: DcInactiveState
disconnected with last try
at 5:38 PM
fail because Radio Not
Available
(everything else here is 0)
The preferred network type is "WCDMA preferred". Whatever I change it to, it sets itself back to that (ref bingley's solution http://forum.xda-developers.com/showthread.php?t=921812).
Turned off and on the radio a few times to try to make it see reason. No joy.
So - did I forget anything?
Can anyone help or offer any suggestions of something else I can try?
TIA for any thoughts anyone may have

Seems like you covered about all the bases. Funny, as it happened to me earlier this week. Exited a metro tunnel, had the same message. But a normal reboot fixed it.
Hope it's not a sign of things to come.

Thanks for the reply. I had no hint or warning that the phone was even thinking about considering doing this for me. No previous network issues beyond low signal ones. I've had the Desire since August 2010 and, up to this point, been loving it. Frankly - broken hearted right now :-(

Might try cleaning the contacts on the phone/sim with a little iso alcohol on a q-tip (cotton swab)
I'd try anything "outside the box"
But I'd guess the radio might be cooked. hardware wise.

While you're flashing, might as well flash your bootloader....

Any recommendations? I'm using the ClockwordMod recovery already. Really appreciating the input - any thoughts are better than silence!
As for the SIM card, I have put a brand new SIM into the phone - clean contacts, straight from a sealed packet - and put my SIM in an old SE handset I have so that at least my number is on air. The SIM works just fine. Someone suggested that I could put some tape on the back of the SIM card to improve contact, but I really think that something more fundamental is wrong here.

Update: My SIM does not work in any handset. The Desire will not connect to any network using any SIM (but shows a decent signal level).
The behaviour is as if both SIM and handset are barred. When I call my mobile number from a landline, instead of voicemail or "This user is not available right now" I get a UK "number unobtainable" or "disconnected" continuous tone back, like the number no longer exists.
O2 are claiming that both the SIM and the handset are damaged and that I need to visit one of their stores. I am feeling that something has gone wrong with their routing system for both my handset and my SIM.
Does anyone reading here have any definitive knowledge in this field that can help when I eventually do get my backside to the O2 shop?
Or does anyone have any theories?

The only thing I can think of, is that you reached a max number of transmissions.
But, I think that may be only from one of our moscow providers, and shouldnt apply to you. Basically, you do 100,000 transactions, and the sim card goes TU. But that was 3 yrs ago.
Sounds like your provider has things mucked up, especially if the sim doesnt work in any handset. I would suspect your IMEU is also blocked, but the local guy at the store doesn't know how to deal with it.
Flash it back to a stock ROM, and go raise cane at the providers store, and get a new handset.

The handset isn't from my ISP, so they are not going to replace it whatever happens. I would have to get out the HTC warranty (which should still be valid).
I can easily flash back a stock ROM - I have one all ready to roll on the SD. How about the root access - would I need to unroot it too?

When you flash back to a stock RUU ROM, is usually nulls the root access.

O mate, I have the exactly same problem! !!!!!!!!!!
Let me know if u got it fixed
I bit think it might be a virus from market.
—-- check what I post in CM's forum -----------
I'm not sure if this is the phone problem or ROM problem or SIM problem. Just post here to see anyone can help. Thanks in advance.
I've installed CM7 for over two weeks, with everything working great! But this morning, my phone showed a notification with "No SIM Card. Emergency calls only".
Well, here are what I tried to solve the problem:
1. I tried to open my phone, remove the battery and SIM card and cleaned it and insert again (i'm 120% sure it's in the right direction, it has worked fine for months!) didn't work.
2. I re-installed ROM and still "No SIM Card". btw, I tried to install Leedroid and CM7 again.
3. I reset the phone to factory setting and erased/format the SD card, which i saw somewhere online.
4.I checked the "Location & security" - "Set up SIM card lock" and found the box of "Lock SIM card (require PIN to use phone)" is ticked, I don't remember i did this! and I tried to input some PIN like 0000 or 1234. didn't work. I thought it might be the SIM card problem then, and emailed my phone carrier about the PIN. but I removed the SIM and rebooted the phone and re-checked the SIM card status, the "Lock SIM card" box was still there. Ok, I got really confused in here now.
my phone carrier replied to my email, telling me to try SIM card in other phone, if it requires PUK, they will give me PUK. (I will do that tmr) I'm thinking of trying some friend's SIM in my phone to see if the problem is in the phone hardware.

Did you try another SIM in your phone? In my case both the SIM and the Phone seem to be blocked/barred by O2 (my service provider).
Unlike in your case, my SIM is not seen as "no SIM" but as one not allowed to connect to the network. It has the same effect in other handsets and no SIM will allow my phone to connect to any network. Also, my phone does not have the "SIM lock" option ticked.
Next step will be to RUU the phone.
I intend to go to an O2 shop on Tuesday to see what they say there.

Next step will be to RUU the phone.
Click to expand...
Click to collapse
if you mind me erupted in this post, i wouldn't flash a rru rom since my feeling is not hardware related... if so wifi won't work at all neither sometimes 3g data.
have already use thetering?? already read that some provider close the connection if so.
I would try some other provider sim, some of them gives sim for free as prepaid.
this is just my feeling about
hope this help

Agreed - I wouldn't recommend RRU flashing unless about to claim on warranty / return the phone to the supplier. Since I have been advised by my service provider to take the phone to one of their shops I feel that it would be better to RRU first.
Yes, I have used tethering, but that is perfectly allowable in the UK and on my O2 unlimited data contract.
As I said earlier, I have tried other SIMs in my handset

iviarck said:
Agreed - I wouldn't recommend RRU flashing unless about to claim on warranty / return the phone to the supplier. Since I have been advised by my service provider to take the phone to one of their shops I feel that it would be better to RRU first.
Yes, I have used tethering, but that is perfectly allowable in the UK and on my O2 unlimited data contract.
As I said earlier, I have tried other SIMs in my handset
Click to expand...
Click to collapse
so what i have already expeienced about 3G data connectivity in my neighborought.
no data connection allowed, each time a went to wireless&network/mobil network uncheck and check to see if it was able to connect, it said fail... send mail to my provider... gives me answer they gonna see blabla...
it s only few days later that i learned that they were "fine tuning" their network for improvement... hope i did'nt flash radio rom or whtever things like this.
if i were in your shoes, i would wipe /data (place where the settings are store) and set the apn settings once more (i have read that you had made factory reset isn't it?) so anything would be lost.
hope this help

fragargon said:
no data connection allowed, each time a went to wireless&network/mobil network uncheck and check to see if it was able to connect, it said fail
Click to expand...
Click to collapse
My problem is a lack of connection for incoming / outgoing phone calls and SMS. Despite a decent signal level, I have the status "Emergency calls only" and when calling my number, I get a "Number Disconnected" or "Unobtainable" tone. This seems to indicate a phone with a barred IMEI. The SIM doesn't work in other handsets, indicating a barred SIM too.
fragargon said:
if i were in your shoes, i would wipe /data (place where the settings are store) and set the apn settings once more (i have read that you had made factory reset isn't it?) so anything would be lost.
Click to expand...
Click to collapse
I did do a reset / wipe. I made and Nandroid backup first, so when the test failed, I simply restored my settings from backup. The issues I have are not related to the APN settings, which I know inside out and can redefine (as I have done a few times) easily.
Thanks for the contribution to the thread

hi, still me
this really annoying, would suggest to cut the piece of cake or its phone related or it s provider related...
if from your mobile setting/about phone/phone identity... you should see 6 different information like :
model number + imei + iemei sv + de serial numb + phone number (not the one from provider) + imsi
you can also check your RIL through terminal with
Code:
su
getprop "gsm.version.ril-impl"
message => HTC-RIL 2.2.0028hmi (date)
THIS IS FOR MY CASE working with my radio (embedded i have not flash any RIL and would not advice to do)
only to check up if everything sound good with your phone... this smelt a provider related.
hope you can sort this

Here is my ril implementation code:
Code:
# getprop "gsm.version.ril-impl"
HTC-RIL 1.6.1062G (Apr 23 2010,17:35:06)
In the about screen, I get the following information:
model number: HTC Desire
imei: (my IMEI number - matches the one printed inside, behind the battery)
imei sv: O2
de serial numb: (not present in UK information)
phone number: (not the one from provider) - only the one from my provider shown
imsi: don't see this listed nor do I know what it is.
How is the cake cutting looking so far?

hi, so far smelt a sim card/provider problem
’International Mobile Subscriber Identity (IMSI) is a unique identifier provided by the sim card - allow gsm or umts identify the mobile user... and it's given by the sim card
have a look on this
Code:
International Mobile Subscriber Identity ( IMSI):
Each registered user is uniquely identified by its international mobile subscriber identity (IMSI). It is stored in the subscriber identity module (SIM) A mobile station can only be operated if a SIM with a valid IMSI is inserted into equipment with a valid IMEI.
There are following parts of an IMSI:
Mobile Country Code (MCC): 3 decimal places, internationally standardized.
Mobile Network Code (MNC): 2 decimal places, for unique identification of mobile network within the country.
Mobile Subscriber Identification Number (MSIN): Maximum 10 decimal places, identification number of the subscriber in the home mobile network.
more info on http://www.tutorialspoint.com/gsm/gsm_addressing.htm
so it s definitively a problem of sim card/provider...
hope this help you mate
edit: i got one and each mobile user with sim card should got one, it's a "secret" number associated with your "public" number which is known by everybody... your number call

Just to close the issue here and to offer up pointers for anyone with a similar problem, I now have some answers.
It turns out that on April 20th, my IMEI was blacklisted in error. According to O2 the bar was placed on the central database indicating that the action was taken by Vodafone. O2 have tried to lift the bar but the attempt was rejected because of the Vodafone flag.
Vodafone have never heard of my handset nor did they request any such blacklisting. They cannot lift the bar because the phone was never under their control and the number doesn't exist on their system. Their system will not allow them to handle numbers and IMEIs they don't have authority over.
This means that O2 are mistaken and that someone at O2 must have placed that entry in the barring database and then flagged it as Vodafone's work.
Just to make this quite clear - my phone is my own. Nobody says it was or has ever been stolen. Nobody has any track of a request to bar it. This is a freak accident or error, like none they have ever seen before.
So I am currently caught between the two service providers, each claiming it's the other's fault and neither able to fix the problem.
Next step - UK Ofcom.
... unless anybody out there knows of a way to make someone own up and correct this error? (no - I don't want to re-program my IMEI number).

[Q] Full signal, cant make calls, no internet access

Hi Guys.
So received the phone on Thursday, Friday I did a sim swap from my normal sized sim to a micro sim. I waited the whole day but the phone didn't have any network access.
Today when I woke up I I switched the phone on hoping that everything will be fine, thinking the simswap just hasn't gone through yet, still no network access. I took out the swim from the phone and switched with my ipad, the sim was working in the ipad, and the ipads sim also didnt give the phone network access.
In the top right corner it shows full bars in grey, cant make emergency calls or anyhting.
In the about section of the phone, I have ALL the details present, baseband version is there, kernel version is there.
In Status section, network is unkown, signal strenght is -83 dbm 15 asu, network type unkown, service state is out of service, and the rest is also present.
I thought the phone didn't properly register to a network, so went into settings - wireless networks - more settings - mobile networks, but it gives me a insert sim card message.
The phone is reading the simcard fine because it asked for the PIN when switching on.
When trying to make a call I get, it says "Not registered on network"..
So what am I to do? Vodacom can only pickup the phone and exchange it on Tuesday, so was hoping that this might just be a software issue that can be resolved by a flash.
I have tried resetting / hard resetting the phone numerous times.
Its the Note 2 N7105 LTE Version
Any help would be highly appreciated.

Try this
http://forum.xda-developers.com/showthread.php?t=2014982

If you bought it new dont flash anything and send it back. At this stage you dont need to make things complicated
Sent from my GT-N7100 using xda app-developers app

dr.ketan said:
Try this
http://forum.xda-developers.com/showthread.php?t=2014982
Click to expand...
Click to collapse
Great thanks.
I tried this but didn't solve the problem. I am using the same sim that I received from the carrier with the phone they shipped.
I have played around in the menu however, maunally setting the band and so forth, just restarted and started receiving sms, so basically if not for your post I would not have solved this.
Thanks

I have isolated the problem.
In the service menu - UMTS - DEBUG SCREEN - PHONE CONTROL - NETWORK CONTROL - SERVICE DOMAIN
There are 3 options
1 CS + PS
2 CS ONLY
3 PS ONLY
CS seems to be for making calls and sending smses
PS seems to be for data connections (When this is selected, the bars are replaced with a circle with a stripe through)
I Could be wrong with the above, so anyone with experience please shed some light
Those 2 work seperately, but when CS + PS is selected, none of them work? Very odd, anyone know what the issue could be?

anyone?

No signal/Unknown Network

Hey Guys
Got a Nexus 5X I need to fix for someone and I'm a bit stuck. Supposedly it happened out of the blue for the user without anything like being dropped etc. The phone when a SIM card in inserted never registers onto the network, it gets the empty outline signal symbol without any bars and shows "No Signal"/"Emergency calls only"
The SIM gets detected when I unplug/replug it in. I have tried multiple working SIMs as well without luck. The phone also does show the IMEI number and also the Baseband version so I don't think it's a problem with the radio software wise.
What I have tried is the following;
Flashed STOCK ROM over itself.
Flashed CUSTOM ROM on the phone
Flashed only the radio img over itself
Reflowed the board thinking the SoC might be at fault
What I don't know is at this point is it a software issue or hardware issue? There should be nothing stopping it from getting a signal as the phone isn't showing no baseband or no IMEI number. It just stats unknown network and not registered for network when you go into the About > SIM status
Anyone know a way of sorting this out? :fingers-crossed:

I also have the same problem. My 5X can detect the sim card but doesn't show any network. Hope someone can give a solution to this problem.

I am having a very similar (or identical problem). My phone detects the SIM card but shows the 'service state' as "Out of Service" and the 'mobile network state' as "Disconnected" Under the network settings it appears that the phone recognizes my mobile carrier and has the correct APN settings best I can tell. In my case I think its likely that I screwed something up when wiping the phone and installing a custom ROM. I think I may have somehow screwed up the EFS partition. I dont know for sure, but ive read that this can be the source of mobile connectivity issues.

A505U can't access Visible network

I've tried everything, so hopefully someone can shine some light into this issue.
I bought a new (unused but from a 3rd party) Samsung Galaxy A50 (A505U) Verizon branded and unlocked. Got a sim card from Visible and went to get it connected. Nothing. WiFi works, everything works, but no cell service.
Here's what I've done (some multiple times)
- reset everything to include network settings, hard reset, etc
- removing the sim, resetting, putting the sim back in. I always get a notification saying the sim card is removed and it goes away when I put the sim back in, so it is recognizing a sim card is in there
- switched sims with another Visible phone/sim and nothing. Both sims worked on other phone but neither worked on this phone
- tried getting into the hidden menus but none of them worked
- talked to Visible tech support which upgraded the issue to the highest level and concluded it's the phone
- Visible believes it's the APN settings but I cannot edit current APNs nor add new ones (grayed out)
- manually add networks, I can see Visible, TMobile, ATT, and some weird numbers, but when I try to connect to Visible it says cannot register on the network, other networks say the sim is not setup for them
- sometimes I get the icon that shows all bars but they're grayed out, sometimes it shows 3-4 bars lit up, sometimes even shows a 4G icon, but mostly the grayed out bars
- sent the phone to Samsung, they tested it and found no faults, guess the hardware is good, ruled that out.
- got into dev options but I'm aware the OEM unlock is not on option on the A505U, not sure if I can change anything else.
I'm out of options. Any other ideas? I think if I can either get into the hidden menus I'll be able to diagnose it better, or if I can somehow change the APN settings I'll be able to set it up. Visible tech support thinks it's the APN, which makes sense to me, but I can't change them.
Any help is greatly appreciated.

I was able to get into the CSC change function, there's not many there, but would changing the CSC help? If so, which should I go to?

I've had a similar issue. Was working fine until the Android 10 update arrived. Since then, it won't work with my total wireless sim card. Tried 3 different sim cards on it, but nothing. Can't add it do anything with the APN, and getting into the phone info hidden menu doesn't help any. I suspect it's a bug in the new firmware or something like that. Works fine with a Verizon SIM though.
Update: Verizon SIM no longer connects to phone. Still works with LTE data. It seems that the CDMA radio quit working with the update to Android 10. Must have been collecting to the Verizon network with VoLTE until it updated the provisioning or something.

So, I finally figured out a workaround for mine that was able to get both data and voice networks to connect while using total wireless, which is an MVNO on the Verizon network. I pretty much narrowed it down to being an issue with the modem not working with CDMA. What I did was download the last Android 9 firmware and flashed just the modem (file starts with CP_) using Odin. After that, I rebooted it and voila! It connected.

Just thought i would give my experience as i just delt with this. i got my 10 update this morning nd let it update and apon a reboot i lost all mobile connection, a signal bar would show for a few seconds looking like it was trying to lock in a signal and it would go back to the ⌀ symbol. i tried flashing the android 9 modem from 2 different updates and neither fixed it. i just decided to order a new phone as i feel its time anyways. my next attempt will be to flash android 9 back using odin then just throw this phone up on craigslist
edit: odin successfully flashed back to android 9 and signal now works again. so if anyone has this issue you can try the method above of just flashing the modem and if that doesnt work you can go back to 9 and restore functionality of verizon mvno's

darkmage1991 said:
Just thought i would give my experience as i just delt with this. i got my 10 update this morning nd let it update and apon a reboot i lost all mobile connection, a signal bar would show for a few seconds looking like it was trying to lock in a signal and it would go back to the ⌀ symbol.
Click to expand...
Click to collapse
Out of curiosity, which carrier are you using?

TJay99 said:
Out of curiosity, which carrier are you using?
Click to expand...
Click to collapse
Visible

samsung a50 not connecting to VZW towers (red pocket)
My phone is doing the exact same thing and while I can appreciate how you resolved the issue it doesn't make much sense to me.
I use Red Pocket for my network. (Which uses Verizon towers - I use the CDMA Sim)
Before this major update to 10 my phone worked flawlessly. Now it won't connect to the network much like you guys have stated in this thread. Mine will connect intermittently for like 3 or 4 min tops and then get kicked off the tower and will actually not show any bars (Circle with a line through it) to show no service for about 10 or so minutes then restart the whole process.
I also have a work phone (2nd phone) that is directly tied to the verizon towers on the verizon network. If I take the sim out of that phone and put it in my samsung a50 the samsung a50 is happy and can make phone calls, send texts, and stays on the vzw towers with no disconnects.
If I take my red pocket sim card and place it in my work phone that phone also works just fine - send messages, make phone calls, and stays on the vzw towers with no disconnects. (work phone = iphoneXR - it's free, sue me)
Even though reverting the modem obviously fixes your issue I do not think that is the actual problem. It also doesn't seem that a third party carrier is being randomly booted off the towers, it seems to be a glitch with third party carriers using third party sims utilizing this new android 10 software that VZW towers do not like.
Which obviously points to an issue with Samsung's latest software not being compatible with third party carriers.
I can't seem to contact Samsung in a direct manner to resolve this issue as they want me to take it to a third party store to have it looked at. I spent 2 and half hours with tech support from red pocket and they came to the conclusion that VZW was doing "upgrades/maintenance" to their towers in my area. (whatever that means.
Any ideas on how I can contact Samsung directly to detail this issue to them? I really do not want to have to root my phone in order to use odin to set my modem back to version 9 as I'm hearing that doing so voids all kinds of implied warranties with the phone and it's only 6 months old.
Appreciate any help that you guys might be able to steer me towards.
Thanks.

Before this major update to 10 my phone worked flawlessly- They Told you the answer, Odin # 9 or if its under warranty take it back Good luck.

My phone (SM-A505U) wasn't even working on visible before android 10.

See my post at the end of this thread: https://forum.xda-developers.com/ga...official-firmware-t3955727/page2#post83845605

I have that problem too. Where I can download v9. I got the Odin.