Your device is not connected to a mobile network if the status bar of your iPhone or iPad (Wi-Fi + Cellular) displays No Service or Searching. Your device can still place emergency calls even if the status bar just displays SOS or “SOS only.”
Verify your service area.
Make sure a mobile network is accessible where you are. Turn off and then back on your mobile data. Select Cellular or Mobile Data under Settings. Depending on your iPad model, you might see Settings > Mobile Data.
Make sure your smartphone is configured for data roaming if you want to travel abroad. Access Data Roaming under Settings > Mobile Data > Mobile Data Options.
Why does my phone say SOS
Indicating a cellular network issue is the SOS icon or SOS-only text, which often appears in the top-right corner of your iPhone on iOS 16 and the top-left corner on prior versions.
Consequently, you are unable to place or receive normal phone calls. You can still call for help in an emergency nonetheless.