Please submit logs from both sides (player side and server side) and also the nomachine configuration files (both sides, player.cfg and server.cfg). You can send everything to forum[at]nomachine[dot]com.
For the Player side logs, be sure that the client has been launched with the ‘Don’t delete log files on exit’ option enabled in Settings -> Player -> Security. On the server, nxserver --debug --enable all
from a terminal enables the debug logs. Start your session, reproduce the problem and then extract the logs. Instructions are available here: https://kb.nomachine.com/DT11R00182