I have a two year old, AT&T cobranded Samsung Galaxy S20 Ultra, which as of today (4/30/22) can no longer make or receive phone calls:
- When I try to dial out, the phone immediately goes to "call ended", as if I hung up
- Incoming calls don't go through at all. Moreover, the call hears that my mailbox isn't set up. Normally, I used Google Voice for voicemail, and that had been working fine until today
- All other features, including data over wireless and SMS, work perfectly fine. That is, these work fine when WiFi and Bluetooth are disabled, so it's definitely connecting over the AT&T network
Troubleshooting thus far:
- Tried rebooting the phone, going into safe mode, refreshing the connection from att.com/support
- The phone and all apps are running the latest versions available - no updates pending
- I removed the Google Voice app in case it was causing any issues
- I tried using the MMI codes (e.g., ##61#) to disable forwarding to Google Voice, but get a connection error (801) when sending the code
- Spoke with customer service on the phone and went through all their troubleshooting steps, including resetting network settings. He eventually suggested I replace the SIM
- Went to at AT&T store and bought a new SIM, which didn't help. They did mention they have had other customers in this week with similar problems with other Samsung phones. However, I can't seem to find anything by Googling around
- SMS and data work perfectly fine over the AT&T network (when disconnected from WiFi and Bluetooth) but still cannot make or receive calls
- Tried everything I can think of short of a full factory reset
- My wife's phone on the same AT&T account, and my work-provided AT&T phone, all work normally from this. I've never had any connection issues in the past in this location
- Phone shows 5 bars for signal strength, and connected to a 5Ge network
- From the SIM card status menu, Mobile Network State = Connected, Service State = In Service, Mobile voice network type = LTE
- Phone = AT&T co-branded, network locked, SM-G988U
The guys at the AT&T store suggested waiting for AT&T or Samsung to push out a fix for the issue, since other people have had the same problem. They said when they contacted the AT&T home office, the person they spoke with said they were aware of the issue. However, I haven't been able to find anything online about it - you'd figure if it was a fairly widespread issue, there'd be forum posts or news about it somewhere.
Any suggestions on next steps? Full factory reset isn't really an option - I'd sooner buy a new phone and make sure I've transferred everything successfully before wiping my current one.
Solved! Go to Solution.
You know what: I just tried something I should have tried before, but just now thought of it.
I swapped SIMs between my personal (broken) phone and my work phone. The work SIM in personal phone worked perfectly; the personal SIM (that I got from the AT&T store today) in the work phone had the same error.
So, it's probably not a cache or setting issue on the phone, but a problem with either the SIM, or my account, I'd imagine?
Yeah, the new SIM on my personal account in my work phone was not working; the work SIM in my personal phone was.
With that info, I figured I'll try AT&T support again, since now I know it's something on their side... and lo and behold I got someone who knew how to fix it. He re-enabled Voice over LTE... and yeah it works fine now 😛
Thanks for your help! Glad I got it working again, without taking up your entire evening :). I'll monitor it to see what's happening, but hopefully it's good to go now.
The fun part with AT&T support - I mentioned the "IMS not registered' issue to an earlier person, and they had no idea - insisted on going through troubleshooting. This guy, as soon as I mentioned it he's like... "yep let me check... oh here it is."
It's completely a crapshoot as to whether you get a good tech. I guess instead of going through troubleshooting repeatedly it might be better to politely end the call and try again.