Sorry if this is a re-post, but… I think I have exactly the same issue as described in this thread, closed in December 2013.
Basically, when I try to exit the NX server from the GUI, it asks for a password, I provide the root password and it’s never accepted. it’s the same when I try to change the NX port. I can change though some aspects of the configuration – I’m able to change whether USB devices, local drives etc. will be allowed.
I’m using Ubuntu 12.04 with kernel 3.2.0-58-generic, NX version 4.0.362-1.
Are there any news about this feature being fixed? When is version 4.1 expected to be released?