Error message Server not installed or NX access disabled

If you see the following error message it means that the nx user's public key was not accepted.:

NX> 203 NXSSH running with pid: 6721
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 200 Connected to address: 192.168.2.21 on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
NX> 204 Authentication failed.

This can be caused by a couple of things.

1. the nx user's authorized key file /var/lib/nxserver/nxhome/.ssh/authorized_keys2 is incorectly named.
   The Slackware sshd daemon is configured to look for an authorized key file named .ssh/authorized_keys not .ssh/authorized_keys2. You can rename the authorized_keys file but it might be better to reconfigure sshd_config, because the nxserver –stop command renames the .ssh/authorized_keys2 to .ssh/authorized_keys2.disabled to prevent access via an nxclient
2. sshd is not running or is incorrectly configured.
   At minimum you need PubkeyAuthentication yes in the sshd_config file
3. The server and client public keys might be different.
   At install the server and client use a default key which should be changed. You can open /var/lib/nxserver/nxhome/.ssh/authorized_keys and compare its contents to the key stored in the client by:
   1. Open the client tool
   2. Click the Configure button
   3. Click the Key button on the General Tab
   4. Ensure that the key matches the key found in /var/lib/nxserver/nxhome/.ssh/authorized_keys on the server
4. This issue can also be caused by a locked user account for nx
   You will notice a locked account by examining the /var/log/messages file for lines like these:

   Feb 25 23:15:48 teepee last message repeated 2 times
   Feb 25 23:18:17 teepee sshd[11597]: User nx not allowed because account is locked
   Feb 25 23:18:17 teepee sshd[11597]: Failed none for invalid user nx from 192.168.0.111 port 49337 ssh2        
   Feb 25 23:18:19 teepee sshd[11597]: Failed password for invalid user nx from 192.168.0.111 port 49337 ssh2

   1. Check to see if the nx account is locked:
      passwd -S nx
   2. If the password is locked, you can unlock it with:
      passwd -u nx
      If that fails because of this error:

      passwd: unlocking the password would result in a passwordless account.
      You should set a password with usermod -p to unlock the password of this account.

      then you can assign a random password (it will never be used) to user “nx” using this command:
      usermod -p <randompassword> nx
      and then unlock the account.