Update if anyone else finds this thread and has a similar problem.
Did some research yesterday:
And it happens from time to time apparantly but unclear why.
Powered down all of my Sonos devices (7), rebooted all of my networking equipment as well and eventually got 6 out of 7 devices working. I have three Sonos 1:s 2:n Gen, two of them are working now but I can’t get the third to work for some reason.
Same behaviour as, everything works but TTS.