Hi @Tumpi
Welcome to the Sonos Community!
Apologies for the delay - I hadn’t come across this service before and needed some help of my own! We were unable to reproduce this issue in our own testing.
Please log in to the Soundtrack Your Brand website with the account used on Sonos. Remove the location(s) relating to your speaker(s). Once done, go to the Sonos app and remove Soundtrack Your Brand from Sonos (Settings » Services & Voice » Soundtrack Your Brand » Remove Account).
Next, add Soundtrack Your Brand back on to Sonos (Settings » Services & Voice » Add a Service » Soundtrack Your Brand).
Test playback - if it still does not work, please submit a support diagnostic and reply here with the number given. Thanks.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein