It could be any of several things, and there isn’t enough detail to be certain.

I’d start by reading the wifi interference FAQ, and applying as many solutions found there as possible.

I would follow that by a network refresh, by unplugging all Sonos devices from power, then rebooting the router. Give the riuter a couple of minutes to come back up before plugging in your Sonos devices.

Finally, if neither of those work, I would 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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.