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Original topic:

Can't make or receive phone calls on an AT&T S20 Ultra

(Topic created: 04-30-2022 06:06 PM)
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userRLofioEJFo
Cosmic Ray
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Galaxy S20

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


Current status:

  • 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.

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38 Replies
Cass94
Nebula
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Galaxy S20
Wow yeah I sometimes forget that the person I'm talking to doesn't know everything we assume they do.... but you just reminded me why I always end up with the supervisor at these places honestly I wouldn't end a support call with any company until they fix it or escalate it to manager because I can't tell you how many times the agent couldn't figure it out or said it wasn't them and then the supervisor fixes it instantly just like with yours
Spursnation210
Constellation
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Galaxy S20
I've been having an almost similar issue on my S22 Ultra (Unlocked) since day one that I received and activated my phone. I'm with Sprint but now t mobile since they've merged. I get a blocked symbol at the top of the phone where the signal bars are located and I basically lose phone service (calls, text and internet) If I try making a phone call I get a pop up message saying " Your phone's not registered on a network, so you can only make emergency calls". I've been to the t mobile store and had them switch my Sim card for a new one with no luck, I've also spoken with customer service like 6 times and technical support also with no luck. All this has been going on since February 22 of this year.
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userRLofioEJFo
Cosmic Ray
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Galaxy S20

I guess only thing I've learned from this is, it might be worth putting your SIM in another T-Mo phone to see if it works.  They'd probably let you do that at the T-Mobile store, for troubleshooting.

If the SIM works in another phone, then the problem is with your phone.  Otherwise, it's with T-Mobile.  Probably.

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Cass94
Nebula
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Galaxy S20
When you contact t-mobile next time explain the issue and tell them you've gone through troubleshooting with them and still hasn't been fixed and you want a refund on your service since you can't use it... sometimes they drag their feet if it isn't costing them money but the second you ask for a refund you'll see they care a lot more about fixing it... but like his issue if you've done a sim swap then it pretty much eliminates the phone as the issue...you could try converting your sim to an esim(although I've heard of this causing issues as well) and see if that fixes it...sounds like your phone keeps disconnecting from sim (maybe there's a physical issue in your sim slot could try cleaning it)
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Cass94
Nebula
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Galaxy S20
One VERY important note about t-mobile
They have TWO kinds of stores but you would never know cuz they don't tell you this and the stores all look the same;
Some stores are just "authorized retailers" for t-mobile and then some are actual t-mobile brand stores...
The difference in knowledge and ability to fix and help with your account is beyond night and day
I could tell you some stories lol just make sure you don't go to the "authorized retailers" should tell you if you Google address
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Options
Galaxy S20
I had AT&T and they SUCK! I would never use their service again.
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jkolaske
Constellation
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Galaxy S20
I too am having same issue. It started with my note ultra 20, couldn't make a call, sim card not registered, everything said above. I have US Cellular. I complained to customer service, numerous times to store and IT. To no avail. I talked to IT and told them I'd go to different carrier. They had me send it to Samsung and everything came back normal. Called carrier again and the decided to pay out rest of note ultra 20 that I owed and upgraded to ultra 22 plus and still dealing with it. Nothing changed. Can't make phone calls, emergency calls only to where I use to be able to use phone. Doesn't happen all the time. Any feedback would be greatly appreciated. Thank you
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lefins
Astronaut
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Galaxy S20

Hey, same problem here 😞

Did you managed to fix it ?

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codehunter
Astronaut
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Galaxy S20
Old post but this still happens to ppl. Check to make sure your apn is selected, then *#*#4636#*#* in the dialer. Make sure bands select your country, Refresh then update carrier configuration, set d n s allow. Make sure you have the correct selection of nr lte wcdma selected or whatever your address uses, Check immediate refresh rate. Then ping test and all test should come back successful
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