Since upgrading to the S2 controller and (I think) corresponding software in my Sonos system (two Play:1 and one Play:3), the controller keeps losing connection around once per day. The error message is: Unable to connect to Sonos. Learn more.

When switching the speakers on manually, they still work and play the last selected station or playlist, so they are still connected to the Wifi. Only the controller seems to get stuck.

After switching the router off and on again, everything works fine again.