Jun 12 16:40:51 linux-awd8 sshd: Accepted publickey for nx from 192.168.1.17 port 41583 ssh2
Jun 12 16:40:52 linux-awd8 sshd: User usb from localhost not allowed because not listed in AllowUsers
It’s not FreeNX that’s not allowed, it’s your user “usb” that is not allowed to login with ssh. Is this your server and is usb a normal account on the server? In that case go add usb the list of allowed users in the sshd settings.