I assume your phone wasn’t plugged into wall power when the power came back on?
I’d reboot the TVS2 - unplug the TVS2, unpair from phone, wait 30 seconds or more unpairing will probably take more than that, plug back in, re-pair.
If you haven’t rebooted your phone, power it off and restart.
If the above doesn’t solve the problem, delete the app and reinstall.