I have the exact same problem, but on Ubuntu 24.04.3 LTS GNOME server and Windows 11 client.
Both latest versions of NoMachine free version installed.
Ubuntu (server) – 9.1.24_6
Windows 11 (client) – 9.1.24_6
Mic in is enabled, mic forwarding also.
I have attached the logs in zip file.
Also screenshot of the input options.
Thank you for your time.