Please try the following:
1. Hang up and call again.
2. Change the network environment, especially if there are high-speed moving objects such as high-speed rail or a highway nearby.
4. Reinsert or replace the SIM card.
5. Back up any important data (phone number, SMS, etc.) and restore your phone to factory settings.
6. Ensure the firmware is updated to the latest version.
If the issue persists, contact the Nothing Support Team for further assistance.