Check other phones with SIM cards of the same carrier in the area. If all devices are experiencing the same issue, it could be due to an unstable or poor signal quality. In that case, contact the carrier for assistance. If not, please follow the troubleshooting steps below.
You can try to restore all settings:
Go to Settings > System and Updates > Reset > Restore all settings.
*By performing this operation, your phone's network settings, lock screen passwords, fingerprint or face recognition, home screen layout, and other relative settings will all be restored. However, it won't delete other data or files. Please note that this process will not restore settings related to Find My Phone, users and accounts, the device manager, app settings, etc.