If Sonos lost connection to the Home App, follow these steps: Check after every step if the problem is resolved.
- Completely close the Home App and open it again
- Turn the WLAN on the smartphone or tablet off and on
- Restart the Sonos device
- Logout and login again to the Home App
- Restart the Internet-Box
- Reset Sonos, remove it from the Home App and pair it again (first in the Sonos app, then in the Home App)