I got this new S10 from Samsung at Thanksgiving. The SIM was from ATT of my old S7. It has been working fine until Dec 26th I upgraded to Android 10 under noticement.
The phone call is working fine. The signal status is -90 to -113 dbm. Wifi works fine.
However if I go to setting /connection/mobile network/network operator, it is ATT. But default setup is grey out. I remember I was able to search carriers and setup LTE previously. Now it seems they are all greyed out.
I had reset network connection and it did not help. I don't want to do factory reset because there will be many new apps installation reconfiguration.
I googled online and found out there were a few tickets could be associated to this issue. The worst situation is Samsung will replace with a new one.
Is there any other suggestions I can try before I ask for replacement?