Kindly follow the below mentioned step to improve the performance of the device:
Check device network mode settings: Settings > Connections > Mobile networks > network mode SIM1 or SIM2 > network mode.
Check network operator settings: Settings > Connections > Mobile networks > Network operators > Select automatically > OK > Registered on network.
Note: We recommend to set device network operators as LTE/3G/2G (auto connect) mode. Check device network in open area. Kindly check your device in a different location/network coverage area.
For further assistance, register your concern in Samsung Members Application (Samsung Members App > Feedback >Error report > Attach log file for any issue)
