Known issues tend to show up on status.sonos.com
Beyond the steps you have already taken, I’d be tempted to reboot the router first, then reboot the speakers. If that doesn’t change anything, 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.
Hi @Webnoob
Welcome to the Sonos Community!
Sorry to hear about this issue you are having with needing to reauthorise your YouSee Musik account on a daily basis.
Thank you for reporting this to us. We are actively working with YouSee Musik on a resolution, but do not currently have an ETA on when this will be fixed.
I hope this helps.