Our Exchange admin has blocked mobile use for all devices (except BB's) that aren't using MobileIron with a specific PIN code. They did this when we migrated to Exchange 2010 for some reason (IS distributed BB's and iPhones only). I can see ActiveSync is enabled in the Exchange Management Console, but i'm blocked from viewing the specific profile properties dealing with the configuration that's denying me access. I'm still working to get around it via the webmail address though, and I was able to get Touchdown to work in Exchange 2007 mode, but it was very slow to sync, and not worth the $20 for a pro key for me since i can use the browser to check it for free.