We’ll need the logs from the computer you are connecting to (server-side). Please follow the instructions for Windows in the document here: https://knowledgebase.nomachine.com/DT11R00182#1
1) enable debug
2) reproduce the problem
3) gather the logs
I’ve pasted some of the content here of that document.
To enable debug on Windows, open a CMD console as administrator and move to the ‘bin’ folder under the NoMachine installation, e.g:
cd %ProgramFiles(x86)%\NoMachine\bin
nxserver --debug --enable all
The log archive is named as: NoMachine-log-<timestamp>.zip (e.g. NoMachine-log-2018.09.27-11.44.01.zip) and stored in: %PROGRAMDATA%/NoMachine/var/log/archives on Windows 10, 8.x, 7 and Vista or in Documents and Settings/All Users/NoMachine/var/log/archives Windows XP.
Please submit them to forum[at]nomachine[dot]com making sure to reference the topic’s title. Thanks!