I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

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.

Thank you very much Bruce.  I will do this right away.  Didn’t know this was a feature so you have been truly helpful!

You’re most welcome. Please let us know what you find out, I’d love to know the cause.