There’s a better than average chance you’re experiencing either wifi interference, or a duplicate IP address issue. Generally speaking, if you follow the instructions in the new router - installation instructions FAQ, these are lessened, but they are still possible. If none of the solutions on wireless interference work for you, try unplugging all Sonos devices from power, then reboot the new router. Once the router has come back up, plug back in the Sonos devices. 

Alternately, you could submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.