I went through the article and checked the server.cfg files and the UPnP is enabled. I’ve attached the files so you can have a look through and see if there are any errors/things that need changing. I’m not sure how to check whether UPnP is enabled on the router though.
Another thing I noticed when using NoMachine is that the gateway port on my mac works, but when I tick it and restart the server on the linux pc it comes up with the error: ‘Failed to map port to the gateway’.
The linux server is behind a uni router yes. I have not tried connecting to my mac from the linux pc through the internet (only on LAN when testing it out initially). It does work though when connected on the LAN. I’ll have a look at the article you sent and I’ll try and figure it out; if I get stuck I’ll let you know. Thanks for your help!