Hello,
Regarding your second problem. Could you please give us the outputs of the following commands:
sudo -V
sudo -l -U <user>
Could you also tell us how do you put credentials for su / sudo commands on this Mac? Is it in username/password or username@domain/password or DOMAIN\username/password format? It would be very helpful if, after reproducing the issue, you would send us /Library/Application Support/NoMachine/var/log/nxerror.log file. You can attach it to the forum post, or it it’s too big (it shouldn’t be) – send it to issues[at]nomachine[dot]com. Thank you.