I have MC 23.0.94 (64 bit) installed on a Win7 PC. PC and Denon are both attached via ethernet cable to my home network. (Denon via a hub in the living room). FLAC Music plays fine on my local PC speakers (using "Player") but when I select the Denon device under "Playing Now" menu and try to play something I get error "There was a problem controlling the selected DLNA device. Double-check your device, server, and network settings." IP address of Denon is correct in MC. (Playing on the Denon worked before but I have not tried it recently.) I can right click on Denon and I can get to the Denon device setup page so I know MC can reach the device on the network. I have downloaded and run the Whitebear Renderer Tests but am not fully sure how to interpret the results. I have looked at network sharing->Media streaming options and the Denon is set to be allowed for all media types. I also looked at the Windows firewall settings and everything starting with Media Center is allowed. I have rebooted the computer. First I tried a flac file but since I am not sure that is supported I tried an mp3 file. Neither worked from MC, same error. (Note that I can play mp3 files from iTunes, receiver supports Airplay....) Whitebear report is attached.
OK heck. I figured it out and wanted to post details here in case it helps others. 1. My Denon will not play FLAC apparently,only mp3.(boo!) 2. You must right click on Denon in the Playing Now window and select "Show Device Webpage". On the browser window that opens you must "source select" the NET USB input to get to the configuration you need. Then make sure it is set to accept the generic DLNA commands. 3. Now select your music and right click then select to Send To Denon.
But I don't use JRiver to manage any mp3 music, only FLAC. So, until I upgrade my Denon to something that will play FLAC files I will keep using my PONO player in the living room to connect to my Denon and play hi-res. Hope this is helpful to someone.