I have a SharePoint Portal with hundred's of sub site that has unique permission. I have created a SharePoint group in SubsiteA with Read permission and then added the AD Domain Security Group to the SP Group. If I use the check permission to validate a user in the AD group it shows none and it doesn't allow the user(studentA as shown below) to login to site and I'm getting Access denied error.
This group is not distribution list. I have synchronized User profile with SharePoint.
This only happens for few groups.
Kannan