Were you running JRiver on the macs before Sequoia, and were they experiencing the same issue?
Interesting.
Today I was playing to my WiiM with JRiver Media Center via DLNA and after a piece finished, I was slow to find another piece and the WiiM clicked off the amp with the trigger. When I played some music, the VU meter was dancing but the amp was off.
I decided to try another player instead of rebooting WiiM. I stopped MC and used Tidal's Mac APP and chose the WiiM. Immediately, I heard the WiiM trigger the amp but before I could play music, I got a Java error from Tidal:
Uncaught Exception:
Error: WebSocket is not open: readyState 0 (CONNECTING)
at WebSocket.send (/Applications/TIDAL.app/Contents/Resources/app.asar/node_modules/ws/lib/websocket.js:450:13)
at Object.send (/Applications/TIDAL.app/Contents/Resources/app.asar/app/main/tidalConnect/websocket.js:106:16)
at startSession (/Applications/TIDAL.app/Contents/Resources/app.asar/app/main/tidalConnect/sessionManager.js:79:24)
at Object.startOrResumeSession (/Applications/TIDAL.app/Contents/Resources/app.asar/app/main/tidalConnect/sessionManager.js:100:7)
at WebSocket.<anonymous> (/Applications/TIDAL.app/Contents/Resources/app.asar/app/main/tidalConnect/TidalConnectController.js:106:35)
at WebSocket.emit (node:events:519:28)
at WebSocket.setSocket (/Applications/TIDAL.app/Contents/Resources/app.asar/node_modules/ws/lib/websocket.js:251:10)
at ClientRequest.<anonymous> (/Applications/TIDAL.app/Contents/Resources/app.asar/node_modules/ws/lib/websocket.js:1012:15)
at ClientRequest.emit (node:events:519:28)
at TLSSocket.socketOnData (node:_http_client:580:11)
And then Tidal flashed an error that "Tidal can't find the internet device" or something to that effect....it didn't display long.
Then I couldn't select the WiiM from Tidal using either Tidal Connect or Chromecast
I had to reboot the WiiM.
I'm going to send this to WiiM tech support although as mentioned above, I had troubles with another DLNA hardware and it is pointing to some Sequoia handshaking error.
Maybe I'll throw it at Apple as well.
If the Java error makes sense above - let me know.
Update: The above error repeated even after a reboot of the Mac and the WiiM Ultra. I had both Ethernet and WiFi enabled on my Mac and when I shut off the WiFi everything worked again. I can't remember why I had both active - there was a reason for it. But for a month now I had ethernet only and recently enabled both and got the errors.