ssh connections in netxms are performed via agent that is running along with the server. You can try setting debug level 6 for that agent - one way is to stop it via systemctl:
systemctl stop nxagentd
and start in in foreyground:
nxagentd -D 6
Then try running configuration poll for your uniquiti node to see if ssh capability becomes yes. Or try adding a ssh DCI on that node and forcing poll for that DCI. Log of the above agent should have some lines about ssh.
