(Last evening i have added a new shared folder, after that there were some trouble with smb on apple devices. (linux and windows not tested).
I found (and then i remember the same problem some time ago) that the shared folder description has an umlaut. After removing the umlaut, everything works fine again.
NethServer release 7.7.1908 (final)
Linux Kernel 3.10.0-1062.18.1.el7.x86_64