On Kubuntu 21.04, on framework laptop. Both client and server run fine on the machine, but auto update always fails at authentication step.
I tried uninstalling and installing again, no change in the problem.
Note that I have two other linux laptops running the same OS that do not have this problem.
After reviewing a similar thread https://forums.nomachine.com/topic/update-cannot-recognize-administrative-password I followed the link there to instructions on how to collect logs, but those instructions do not match the installed structure on my machine. The link was to https://knowledgebase.nomachine.com/DT11R00181#1.1 but that details a different config file structure, and the specified settings are unavailable in the config files I do have.
I would be happy to help you debug this, so please let me know what I should do to provide more info.