I just recently installed a Russound MBX-PRE streamer to our MCA-66 series due to the issue with SiriusXM compatibility with the XSOURCE streamers of which I still have 2 installed and working. I use Plex for Media streaming with DLNA enabled and the XSOURCE streamers see and work just fine with Plex. While the web config utility for the MBX-PRE shows Media Server as one of the streaming services available for configuration just like the XSOURCE, when you get to the Russound IOS app and keypads, the option there changes to UPnP for the MBX-PRE while the XSOURCE selection remains as Media Server. I am unable to see the Plex server when I select UPnP on the MBX-PRE but on the XSOURCE, I can see and select the Plex server without issue. Interesting that when I select UPnP on the Russound app or keypad for the MBX-PRE, my laptop also on the network shows up as selectable but irrelevant with no content. UPnP is enabled in the router and I am unaware of any other settings required that are not already set for DLNA on Plex. Other thoughts on what I am missing?