Hello,
The free version of NoMachine doesn’t support SSH connections. You should check point 1.3 of the installation guide:
https://www.nomachine.com/DT09K00056
This is why ‘nxserver –checkssh reports an error. This is used by other NoMachine products, which support the SSH protocol.
Instead of using ‘nxserver –checkssh’ to verify your installation you can use:
/etc/NX/bin/nxserver –status
The output of the command should be:
NX> 161 Enabled service: nxserver.
NX> 161 Enabled service: nxnode.
NX> 161 Enabled service: nxd.
In the case of NoMachine (free), ‘–checkssh’ is unnecessary but harmless. We will remove it.