Make sure that your device is connected to a Wi-Fi or cellular network. Tap Settings > General > About. If an update is available, you’ll see an option to update your carrier settings. To see the version of carrier settings on your device, tap Settings > General > About and look next to Carrier.
Why does my iPhone suddenly have no signal?
Service interruptions may be caused by a simple setting change, such as Airplane Mode or carrier settings. In a few cases, the iPhone needs to have its cellular settings updated through a software update from your cellular service provider. Less often, you need to reset or replace the phone’s SIM card.
How do I reset my signal on my iPhone?
Go to Settings > General > Reset Network Settings, enter your password, and confirm that you want to reset your network settings. Your iPhone will restart and once it’s back on, your network settings will be totally reset. Bear in mind, you’ll need to reconnect to any Wi-Fi networks or Bluetooth connections you use.
