See if assigning drive letter, S for example, or any other that's not used helps.
Idea is to type in s: in a windows explorer or even command prompt and be able to see and access all the folders/files.
Also, and I know you said that you don't have any permissions, make sure you can create, edit and delete a file, like a text file.
I've seen some issues where even though the attributes are set correctly, there is still sharing violation and files can not be created/modified from a local or remote machine.

I myself am fighting with some Dahua 4300 cameras trying to record to my local D: drive using FTP protocol. Sometimes it works and sometimes it doesn't.
For me it looks like when I purge the folders, if I delete a specific one, the FTP server loses the share permissions.