1. Check whether the phone is set with call forwarding, flight mode, call barring, etc. It is recommended to cancel and try again.
2. This number has been stopped, which affects the call. You can check the status of the number. If it is not normal, you need to restore the normal state of the number before you can answer the phone.
Please check whether the mobile phone is in arrears. If it has been recharged, you can check the recharge status.
It is suggested that you can restart or switch flight mode and try again. If you still can't answer the phone normally, you can also change your mobile phone for testing. If not, you can contact the local manual customer service.