This is not the problem created directly by NoMachine. On the contrary, PulseAudio needs client.conf file to work properly. Use this template to recreate it
https://github.com/pulseaudio/pulseaudio/blob/master/src/pulse/client.conf.in. Make sure that it has proper permission, owner and group.
Replace @PA_BINARY@ with path to PulseAudio Daemon, possible path is /usr/bin/pulseaudio and set
autospawn = no (simply paste it above
; autospawn = yes) . Then reboot the machine.
If the problem still exists, please send us output of command