Hi, please check this topic here which deals with the same message.
No available desktops on this server (Windows 11 client and OSX Monterey host)
First, can you check that the correct permissions are set on the Mac computer? Here you can find some further hints: https://knowledgebase.nomachine.com/AR09S01139. In some cases, after a OS update, it might be necessary to remove (uncheck) the permissions and grant again.
If that doesn’t help, it could be the same issue we are already aware of and will be fixed in the next software release, version 8. A restart of the nxserver on the Mac machine can sometimes help.
After you’ve tried this, what happens?