Hello,
ThinLinc will first connect to your 10.x.x.x IP, and then disconnect and make a new connection to whatever agent_hostname is set to in /opt/thinlinc/etc/conf.d/vsmagent.hconf
If this is left empty, it will be the primary ipaddress of the first network interface card of your machine.
Try to change agent_hostname to your 10.xxx.xx.xx ipaddress and then restart the vsmagent.service:
sudo systemctl restart vsmagent
Kind regards,
Martin