B1426 and Matrix Audio Element X2 streamer problems

Driving Roon with an M1 Mac Mini, connected via wired LAN to the same physical switch as an Element X2 streamer. Playback via AirPlay works fine, whether grouped with other endpoints or all alone. But if I try to use RAAT playback, it fails after a couple seconds with the dreaded “audio file loading slowly” message. I get the same results from Radio Paradise, Qobuz files, and local FLAC 44k files. I’ve tried restarting everything involved to no avail.

I’ve been using AirPlay pretty much exclusively for the last few weeks on the streamer, so I’m not sure which build broke RAAT for me. But the Element has generally been pretty compatible with RAAT before now.