1, check whether the mobile phone number is in arrears, and contact the corresponding operator to check and verify;
2. Check whether Apple's 5s data network function is turned on. You can enter the settings, select General, click the cellular mobile network to open the cellular mobile data function, and check whether it is normal after restarting the mobile phone.
3. Check whether other mobile phones of the same operator work normally. You can change the phone test first. If there is something wrong with your mobile phone, you can first select Settings, click General, select Restore, and select Restore Network Settings before trying to use it. If there is no improvement, it is recommended to contact Apple for after-sales inspection and verification.