Symptom: the softphone loses its SIP registration periodically.

Common causes:
- The VPN drops and the softphone does not re-register in time.
- The re-registration interval is too high.

Checks:
1. Confirm that the VPN is stable (the VPN supervisor reconnects by itself as of 0.11.0).
2. Validate the softphone re-registration watchdog.
3. Check NAT/keep-alive.

Solution: update the app to the latest version (VPN auto-reconnection and re-registration) and check the computer's network.