Why did Apple's mobile phone information activation fail?

Due to network failure, Apple's mobile phone information could not be activated. The solutions are as follows: tools/materials: Apple 13, iOS 15.0, and settings 15.0.0.

1, turn on the phone and click Enter Settings.

2. On the Settings page, click Enter Cellular Mobile Network.

3. After entering the cellular mobile network page, click Restore Statistics on the page.

4. After restarting the phone, enter the ID account and password, and click the activation lock.