authentication through wireless failed

Hi everybody.
I have a problem with my mikrotik RB751U-2HnD. I have installed in my office a Nas server, which is accessed through network.
my problem is that the users who are connected with wireless fail to authenticate to server and can’t access shared folders.
the server has also a web interface to login, where the credential doesn’t work also. the login works on port 5000.
does anyone have any idea? :frowning:

many thanks