One of the sub folders cannot access

We are using WD My Cloud PR4100 for our data storing and sharing. There are some shares some of them are having password. there is a share with a password and there are many folders and subfolders under this share, today noticed that we cannot access one of the subfolders under this shares, we can access other folders and sub folders. it is showing a meassagewdSubfldrproblm " windows cannot access \ABC\gh, You do not have a permission to access \ABC\gh\ .contact your administrator"…
There is a password only for the share, there is no separate password or restriction to any subfolder.

That folder name may be causing issues. Try not to use special characters.

I think it is not related to name… because before it was working … and same problem came ones before with different name