So progress is there. The problem is that your mount folder (on the side of your new Plex server) doesn't have the needed permissions.What am I now doing wrong? Any suggestions?
The folder that you have mapped your remote location needs to have read permissions for the following account PlexMediaServer
Make sure that that account has read permission on your folder. Note that it is a system internal user so be sure to change the upper left dropdown menu from local users to system internal.
That's the account used by Plex in order to scan for the data.