adding security to network drive

Hello all....
I have a bit of a problem. I was tasked with adding security for 3 users to a virtual server drive. Call it the K drive. ....one person could already access this drive and wanted his three other people in his dept to be able to have full access to this drive to view and edit content.
So it's basically the K drive on the virtual server I right clicked, went to the security tab and added their user accounts and gave them full access.
This morning they are trying to get to this Prism admin (which is located on this server) and it's asking them for login information that it never did before.

Would me adding these accounts with full access to the root of the drive change permissions that are already in place? I didn't change anything, just added other accounts. I've never seen that happen before.....this isn't a share, so it may have diffferent rules.

anybody have any ideas?

thanks

Mike

 

I've since removed the 3 accounts that I added and the IIS admin isn't avaiable either. Not sure if that is connected somehow.
Would running a GP update set things back to the way they were?