Ensure that your library is not going into sleep mode.

Read this as well:

https://support.sonos.com/s/article/4725?language=en_US

Thank you ClausN. I tried that and it did not work!

Any other suggestions? This is driving us just a little nutsy.

If you have ruled out wifi interference as described in the link in my first reply, submit a diagnostic within 10 minutes after the music stops, post the diagnostic number here for a Sonos employee to review or call Sonos Support to discuss it.

While waiting for Sonos to reply, refresh your system, it may prove to be a quick fix:

Power off all Sonos and library, restart router and wait until the router has fully restarted, then power on Sonos and library.

Please post the solution when the issue is solved.

Thanks. We will try that and I will post my response.