TTS on Sonos speakers not working

I’m trying to get TTS to work on my Sonos speakers. I tried Google TTS and Home Assistant Cloud TTS. None of them are working. There is just no output. I tried to adjust the volume but nothing. Do you have any ideas how to find the issue?

My setup:

  • latest Home Assistant running on an Intel NUC
  • valid Home Assistant Cloud subscription
  • Sonos components: 2x Play:1, 2x SYMFONISK bookshelf speaker, Port

Testing TTS in my local brower works:

There is nothing in the logs:

Does nobody have an idea where I could start looking?