We had one more today, someone unable to connect their media player to the UPnP server, being sure everything is setup as it should. Often this leads to blaming one of the devices in the chain on your network, even more regular, people blame the media players and although it can be the player, let's make sure and limit possibilities first.
By using a UPnP scanner on your PC, you can determine if it is only the media player not seeing the UPnP server or all devices on the network fail to see it. Such scanner exists indeed and can be found at the following link:
Simply run it on your PC and see if it shows the UPnP server you are trying to connect with your media player. That will give you a good start determining if it is the player or not...