Spotify Connect not working on desktop

[idi_idi_idi]

It works fine between my phone and home pc, but it doesnt work with my phone and work pc. When I click the "Devices Available" button on the bottom right near the volume, it just gives me the generic description that appears there.

I'm guessing it might be a firewall/port forwarding issue? I can get this sorted by the IT team but how do i know what needs to be allowed access etc?