Turn off Airplane Mode
Check for cellular signal
Restart the iPhone
Remove and reinsert the SIM card
Toggle Cellular Data off and on
Update carrier settings
Update iOS
Reset network settings
Contact your carrier
Contact Apple Support
Turn off Airplane Mode
Check for cellular signal
Restart the iPhone
Remove and reinsert the SIM card
Toggle Cellular Data off and on
Update carrier settings
Update iOS
Reset network settings
Contact your carrier
Contact Apple Support