I’ve recently been trying out a Navidrome/Symfonium setup and just ran into a problem with casting a local network Icecast stream (that I use for my turntable). The radio station plays fine in the app, but if I try and cast it to Sonos the stream doesn’t start.
I remembered the stream had previously worked with Sonos’ TuneIn integration, but when I tried it again it didn’t work (even though it works fine in TuneIn itself).
Looking at the Sonos docs, it looks like streams need to be in MP3, AAC, or WMA to work (I’d been broadcasting FLAC). After switching to MP3, casting from Symfonium to Sonos (and Nest speakers) now works fine!