Tags: SOS, No Service, No Cellular Data, iPhone

Troubleshooting Steps:

1)Hard Reboot of iPhone

Press and quickly release the volume up button.

Press and quickly release the volume down button.

Press and hold the side button.

When the Apple logo appears, release the side button.

2)Network Reset
Go to Settings
Go to General
Go to Transfer or Reset iPhone
Select Reset
Select Reset Network Settings
Enter Passcode and Screen Time Passcode (1937)

3)If other steps fail, switch Cellular Data from Auto to LTE
Go to Settings
Go to Cellular
Go to Cellular Data Options
Select Voice & Data
Switch from 5G Auto to LTE

Workaround (WiFi Calling):

Go to Settings
Go to Cellular
Enable Wi-Fi Calling