I have an old "test" PC in my basement that I access (when I use it at all) via remote desktop. Occasionally I need sound from that PC. Sometimes I can get it via remote desktop; sometimes I cannot. Those times that it works I've done nothing - that I'm aware of - to get it to work; the sound is just there. I have no way of knowing which end of the connection is at fault when it doesn't work and no idea how to diagnose this.

Some of my audio sources have the ability to choose MME, DS, or WASAPI. When the audio does not work, switching interfaces does not help. When the audio does work I've never bothered to check which interface is being used.

Any suggestions no getting this to consistently work would be appreciated.

Both ends of the RDP connection are Win 10 21H1, build 19043.1466.

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Some more information:
After rebooting the remote box the remote audio is working. DS, MME, and WASPI all work as audio source. (Using WASAPI via Remote Desktop hung one of the audio source applications, but I assume that was a problem with the program since WASAPI worked fine with another program.) If the past is any guide, this success is temporary. I will eventually do something that makes it fail.

My attempted diagnosis is temporarily suspended since I currently have no problem to diagnose. However, I'd like to prepare for the next failure. If anybody has any suggestions I would appreciate hearing them.