Hard to tell what might be going on from an external perspective, unfortunately. 

I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. 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.

What was the voice command you used?

It seems pretty reprodiable, so when I have some time I’ll contact Sonos Support with a diagnostic and see if they can figure this out.

The voice command is “Hey Sonos, transfer the music”. Sonos responds ok and then starts playing random children song on the speaker that I want to transfer the music from.

It’s hard to know exactly without also knowing what speakers and rooms you have available in the app.

However, the support article covering List of voice requests for Sonos Voice Control for transferring music has examples where the room names are specified in the voice command.

You may have more success if you make your voice command more specific.

Thanks for your response and I’ll give it a shot next time but this is a command that has worked for a long time and just stopped working a week ago. I’ll update the thread if a more specific command helps.