Hello
The NX protocol key authentication should be generated by nxkeygen command, or if it is generated by ssh-keygen, then should be converted in pem format.
You can convert the existing SSH private key by using this command:
ssh-keygen -p -m PEM -f path_to_the_key
We’s like to check the client side logs, can you send them to us? Please see the document here for instructions and then send them directly to forum[at]nomachine[dot]com making sure to use the title of this topic as the subject of your email. Thanks!
https://kb.nomachine.com/DT07S00244#2