Iris: Snapcast shows as "disconnected", though it works

I’d originally posted this as a bug on the Iris github, but it was closed with the recommendation that I come here, despite the fact that it feels to me very much like an Iris bug…

Running Iris, the interface shows Snapcast as “disconnected”, and I am unable to control Snap through Iris. Disabling and re-enabling Snapcast through the Iris interface has no effect. However, Iris does play through snapserver: playing music sends audio to the snapserver, and the audio plays on the connected snapclients. Furthermore, Snapweb, the built-in snapserver controller, works fine through port 1780 on the same box: I see all the connected snapclients and can individually adjust their sound while audio is playing through Iris. In other words, it seems to me that snapserver can be controlled through its usual port, but for some reason Iris isn’t controlling it (but is playing through it).

If, in Iris, I go to Debug, enter Test Mode, enable the debug overlay, and send the default {"method":"Server.GetStatus"} message to Snapcast, the request enters the load queue, does nothing for some number of seconds, and eventually pops up a “Could not debug Request timed out” alert.

I’m using Mopidy 3.2.0, snapserver v0.26.0, and Iris 3.62.0 on Debian (all running on the same machine). Everything had been working fine until recently, and while I have occasionally upgraded these three (and other) packages, I haven’t made any configuration changes that are likely to have affected this. I have restarted snapserver, Mopidy, and eventually the machine itself. Thank you for any suggestions.