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