Ok, I’m a noob to this so don’t shoot me down.
Hardware: Vera 3 with UI 7, firmware 1.7.569
Problem: Trying to add Jongo S3 render device via DLNA and uPNP
Plugins: DLNA plugin and Universal PNP plugin
Condition: No upnp devices will discover via discovery or upnp device add (upnp not working)
Workaround: Add device manually by specifying DMR URL
This was fine but the damn URL had a manual port specified after the address (proceeding":" then a random port number so 192.168.81.100:3999) which caused device to go offline.
Temp fix was to telnet in and run command: route add -net 224.0.0.0 netmask 240.0.0.0 dev br-lan
Yay now the discovery works, seems all upnp traffic was being dumped or worse router to wan, only problem was every time I rebooted it had to be done all over again. Not being a Linux guy this was now a learning exercise.
Fix: found the Holy Grail for windows UI guys 
Openwrt!!! Factory installed!
Went to:
http://192.168.81.1/cgi-bin/webif/info.sh
Navigate to the System then startup tab, go all the way to the bottom and drop the route add command.
Quick reboot and I now have functioning DLNA and upnp!
Took me hours so sharing in hope this helps someone else, i am not saying this is right or even repeatable but its working as desired now and i can see all devices on the wifi when i click discover.
Last tip, username is root and password is under the device on a label which is the same as default wifi password
, good luck and hope this helps other noobs