What causes a phone to enter SOS mode?

The main reason people ask this question “Why is my phone in sos mode” is due to issues with the network connection. When a cell phone is unable to make a good connection with its phone service provider, it goes into SOS mode. This can occur when carriers lose power or after software changes, or if you travel to low-coverage areas. It can also be caused by an expired carrier plan and/or a broken SIM card. Common troubleshooting steps include a device restart, network reset, and carrier update, which can quickly resolve the problem.