Hello,
firstly, please check if you did approve kernel extensions (see article about it)
if yes,
1. let’s load nxaudio kext manually:
sudo kextutil -vvv /System/Library/Extensions/nxaudio.kext/
2. if you already approved, skip this step:
Access System Preferences -> Security&Privacy -> General panel. Click on the “Allow” button
3. if it finished without any error, check if it’s loaded properly:
kextstat | grep nxau
you should get similar output:
180 0 0xffffff7f83d9c000 0x5000 0x5000 com.nomachine.driver.nxau (4.1.b2) 78172556-B6A4-3112-BA41-E79D18108476 <93 6 5 3 1>
4. restart NoMachine server:
sudo /etc/NX/nxserver --restart
If audio still does not work, please send us the output of kextutil command (point 1) in your reply.