I tried your mp3 file, and the result for me was the same: doesn’t work with Olisto, does work with IFTTT.
My trigg couldn’t be much simpler. Button push triggers action Sonos Play Stream, with the url and a stream name. I used your url exactly as written, and I used the suggested sample stream name Radio 1 just to be sure it didn’t make any difference. Result: “There seems to be a problem with the Sonos interface”.
So if the specific mp3 file and url doesn’t matter, and it works for you but not for me, then by process of elimination the next most likely thing is that there is some kind of difference in the setup of my Sonos account. I’m not aware of anything that could affect this, and as I noted, both my url and yours work with IFTTT playing to the same Sonos.
This is what the IFTTT action that works looks like:
This action will stream audio, such as a radio station, from a URL.
What do you want to play?
Where do you want to play?
(name of Sonos speaker)
What name do you want to show for this stream? (optional)
What image do you want to show for this stream? (optional)
Include grouped rooms?
This room only
(selection from drop-down list)
The only thing really extra with IFTTT is that the particular speaker (Bedroom) can be named, but this is the same as the default speaker selected in my Olisto Sonos channel.
I tried deleting my Olisto Sonos channel, reconnecting and re-authorizing Sonos, and then fixing the affected trigg. No good, same error.
If it helps, I have a single Sonos One (just in case that’s different from what you’re testing somehow).