Use the cloud dial trumpet to indicate that the call failed.

1. Check whether the phone is in airplane mode.

2. Check whether the cell phone signal is stable. If the network signal is not good or there is no signal, please turn it off and restart, and search the network again. If it doesn't work, it is recommended to take out the SIM card and try to insert it again.

3. Check whether the mobile phone has enough balance.

4. If you can dial some fixed numbers, check whether the fixed dialing function is started. It is recommended to disable this feature.

5. Check whether the call barring function is set. If so, please cancel and try to make a call.

6. Replace other SIM cards.

7. Back up data (contacts, text messages, pictures, etc.). ) and restore the factory settings.