Can't access one specific folder in shared drive

I have a specific drive [P:] on my desktop set up for sharing (Properties/Sharing/Advanced Sharing/Share this folder). The drive has several folders. I can access all but one of them through my home network. With the one, I get the message that I don't have permission to access the folder. When I check sharing properties for this folder it shows "Not shared", but so do all the other folders, which I *can* access.

Even if I set the properties for this specific folder to "Shared", where it then appears as a separate folder along with P:, I get the same error message when I try to access it. What could it be about this particular folder that prevents shared access?

FWIW, I solved the problem by copying all the files to another folder, which I then *could* access.