Hi again
I my case toggling of the guest permission had no effect, but I managed to get get the Roon core connected to the folder whit my music by setting up a shared connection to the folder on the NAS; so the to line does NOT work, but the second line does.
Pretty glad I got this to work, as I’m evaluating Roon future use …
Anyway … just a work-around to a bug, which needs a fix 
Kind regards
Jens