We used to have an SBS 2003 server. We migrated all the services to independent Windows server 2008 and 2008 R2 servers. We are running MS Exchange 2010 SP1 in a Windows server 2008 R2 server now. After the migration I noticed that the distribution groups are not working neither the old nor the new. And every time I create a new mailbox no one can find the new email account in the GAL. Maybe this is a simple issue easy to solve, but I'm new with exchange and I don't even know where to look.