Multicast UDP streams are not working

Hello,

I have an issue with Multicast UDP streams (which can be played with VLC with udp://@<ip>:<port>). I can't get any data getting to the VLC client.

Hardware:

Mac Mini (mid 2014, i7, 16GB mem)

OS: MacOS Sierra (10.12)

Network connections:

Onboard: local network (192.168.1.X)

Thunderbolt networkcard: iptv network (10.3.X.X)

In Microsoft Windows it works out of the box, plug in the iptv network cable and open udp://@239.X.X.X:2000 and it plays the channel. When I try this in MacOS there is no video and audio like there is no data traffic at all.

When I search on google with the keywords: "OSX UDP Multicast" there are a lot of results of people who are having issues with this.

What have I tried:

-Make static routings to the thunderbolt network card. Still nothing.

-Change all the network cards to not use ipv6. Still nothing.

-Installed VMWare fusion and installed windows 10 in it, with bridge mode to the thunderbolt adapter. The udp multicast iptv streams works perfectly here. So the network connection itself is fine it appears to me that it's a bug or wrong setting in MacOS.

What I did not try yet:

-Internet restore back to OSX 10.10 Yosemite and try it. Not that I would like this as a solution.

So I have no solution yet what worked.

I even checked it with the support of dvblink for a few hours since I want to use their iptv server solution on the Mac mini and want to get rid of the windows server which I had in house.

Anyone who has a solution about how to solve this?