Chromecast Audio cannot stream audio

Hello,

I also have this issue. I first thought that it was the Chromecast. But recently discovered that it was the UTM. I have not found a solution yet. I'm thinking on making the Chromecast completely open to the internet, so an any- any rule from internet to the Chromecast. Will let you know if this works.

Hello,

I also have this issue. I first thought that it was the Chromecast. But recently discovered that it was the UTM. I have not found a solution yet. I'm thinking on making the Chromecast completely open to the internet, so an any- any rule from internet to the Chromecast. Will let you know if this works.

I have already tried to open the firewall so my entire network can communicate on every port out to internet (but not in).
Did not work, unfortunately. 

Ok, If I'm not mistaken is this what the Chromcast should do. It should make a connection with Spotify directly, so without your mobile in between. So have you also tried to open up the firewall form externall to internall? I think Spotify can't connect with the Chromecast for some strange reason. I will also openup a support ticket at google.

Exactly, the stream goes directly to the chromecast when casting the audio.
No I have not opened (or made any portfortforward) to the chromecast audio from outside the firewall. This should not be neccessary, I think. (I have not found any information regarding which ports are used anyway)
For example works Spotify connect from my yamaha receiver and it is pretty much the same concept I think.
From my mobile phone I choose to play the stream on my receiver and via spotify connect it plays, and 
I have not opened any ports in the firewall. I can see a constant connection to spotify from my receiver so I think the receiver connects
to spotify connect, not the other way around.

I think the problem is Multicast forwarding and/or IGMP but I don't know how to set up this in the UTM. I can't say these sections are not self explained.

I have also found the thread where somebody had problem with the chromecast audio and the UTM and solved it, but sadly he didn't tell how. 
It should be illegal not to say how something was solved when writing in the forums ;) 

It is interestering that I almost can get it to work. The chromecast shows up in the network and in spotify I can choose to stream the content to the chromecast.
When choosing the chromecast the chromecast makes a beep and the phone are trying to connect, without luck tough.
But the chromecast get some information that a stream is incoming, but can't play or can't reach the stream somehow..