Active Directory integration issue with SharePoint

Hello Experts,

Some of users have reported that they are unable to access a SharePoint site. The SharePoint admin guy indicated he gave the group Indicator Catalogue Viewers view only."

In addition to this, all company users should have view access to this site, as they grant access to a group in AD named "OurDomain\domain users"

Ideally when we add “ourdomain\domain users” domain group, it should give permission to all company staff. Somehow it’s not working properly and I would like to know why?

Our environment as per below:

Exchange version [2010 SP3]

SharePoint version [2010 latest SP] [there are a farm of servers]

Windows/domain functional level [Windows 2008 R2]

All client computers are Windows 7 professional SP1

All SharePoint/Exchange/DCs are hyper-v guests and we have a child-tree domain structure

What are the steps to resolve this AD/SharePoint integration issue?

What tools should be used to reproduce this issue?

Any ideas?