iPhone stuck on Emergency mode

Try and force restart it to see if the issues persist i

press and quickly release the volume up button, then press and quickly release the volume down button. Finally, press and hold the side button until the Apple logo appears. 

If you see No Service or Searching in the status bar on your iPhone or iPad (Wi-Fi + Cellular), your device isn't connected to a cellular network. If you see SOS or "SOS only" in the status bar, your device can still make emergency calls.

If you see No Service, Searching, or SOS on your iPhone or iPad

The pic below is self explanatory.