One difference between SSHSession and SSHCommand is that SSHSession can be created with sshkeys but the SSHCommand expects a password.
That is why I was able to execute commands with SSHCommand.
Can you please let me know if there are any configurations that need to be done to get this plug-in working.
The following are the steps I followed,
Added the host to the inventory and also created a new root folder.
Generated key pair using vco default workflow
Registered the vco public key on the host.
Please let me know if I am missing anything