but still try factory resetting it.. that may solve some issues if it's related to your phone.
if you can then compare it to other mobile
Dear Samsung Member,
Greetings from Samsung Customer Support!
Please be assured and to resolve "network" issue please follow below given steps:
1. Check device in safe mode:- Power off the device > Press and hold the Power key for one or two seconds to turn on the device > When the Samsung logo appears, press and hold the Volume down key.
To exit safe mode: Restart your device.
2. Check Network mode and set it to Auto Connect. (Settings > Connections> Mobile Network> network mode SIM1 or SIM2 > Network mode> Select LTE/3G/2G auto connect)
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question).
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Thank you for writing to Samsung.
Samsung Customer Support