What's the *client* Operating System/Distribution/Version that you are
using? (If it's a Linux system, 'cat /etc/os-release' should provide all
the necessary info.)

What's the X2GoClient version you are using?
(Run 'LANG=C x2goclient --version' in the shell to find out.)

Ok so my set up is the following:

Client:
OS: Ubuntu 18.04.1 LTS
X2Go: X2Go Client 4.1.1.1
Server:
OS: Ubuntu 18.04.1 LTS
x2goserver: 4.1.0.0
x2goserver-common: 4.1.0.0
x2goserver-extensions: 4.1.0.0
x2goserver-fmbindings: 4.1.0.0
x2goserver-printing: 4.1.0.0
x2goserver-x2goagent: 3.5.99.16
x2goserver-xsession: 4.1.0.0
Kerberos KDC:
Ubuntu Server 18.04.1 LTS

One outcome might be that we'll have to get you to change to an older or
newer version of X2GoClient and try that.

Do you suggest any versions? We would be doing some trial and error attempts here right?

If you'd like to try replicating, this is pretty much the sutup I have. As for the paid support, it's unlikely that my Uni would cover that.

Regards,

Rubens