Why does the SOS happen?
It just occurred and I had to replace my SIM card…
iPhone 13 Pro, iOS 17
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 mobile 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