Getting a very intermittent issue with the new phone.
Got the Note 20 and use a Samsung clear case with it.
Every now and then and can be days in between I will lose signal and the message "Check Sim Card Tray" pops up. Normally comes up a couple of times and then is ok.
Have tried the sim in Slot 1 and moved it to Slot 2 and same problem. Have tried another Sim in the phone and Sim is ok. All as Samsung support suggested.
Tried another Sim in the phone but still same problem.
Regret beginning to set in.
If you've tried other sim cards that you know work in other phone's then if a factory reset does not help then approach who supplied the phone if not Samsung and either ask for a new phone if your within any cooling off period or if out of the cooling off period go to a Samsung Experience Store or Samsung Service Centre @Divvykev for a diagnostic.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.