I have installed it on my OpenSUSE test server but when it tries to connect to the trakCare server, I get "Connection Refused".

There is no firewall running on my OpenSUSE test server nor the trakCare server.
I've tested this with firewall-cmd --stat.

The trakCare server is SUSE Linux

The main comms firewall is not blocking the transmssion either.
Do you know what ports are being used between OpenSUSE test server and the trakCare server?