Hi, as far as we are aware, Devolutions Remote Desktop Manager supports NoMachine sessions, including the latest version. We checked just to make sure.
Confirm what you are using with regards to NoMachine software (both client and server) and the RDM product version as well.
Additionally, please tell us the steps you are following in order to the produce the error you receive.
If you are using an old version of NoMachine software, I advise you to update to the latest version. We can only provide help here for currently supported versions.