With so little information provided, it’s hard to tell, but I’m leaning toward it being the Mac’s hard drive is being put to sleep by the Apple power conservation settings. 

Isn’t just the Mac it was doing the same thing on my previous Dell. And my Mac settings don’t allow the hard drive to go to sleep unless I power down.

Since you seem to be unable to provide any data from which to draw any other conclusions, I would recommend recreating the issue, then submitting a system diagnostic and calling  Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

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, there are more options available beyond just the diagnostic analysis.

Good Idea.