Please follow the below steps:
1. If the phone line is bad, we recommend you hang up the phone and call again.
2. The network environment is poor, such as weak signal, unstable signal, etc., which cannot meet the requirements of good communication, please try to change the network environment.
3. If there are high-speed moving objects such as high-speed rail or a highway nearby, please try to use it in a different environment.
4. If the SIM card is seriously worn or has poor contact, re-insert the card or replace the card.
5. Backup mobile phone data (phone number and SMS, etc.) and restore factory settings.
6. After backing up the mobile phone data, refresh the phone or update the firmware to the latest version.
If the issue persists, contact the Nothing Support Team for further assistance.