I recently took over an Exchange 2013 server. All roles except the Edge role are on the server. It's integrated into Lync, however, I don't feel that is the problem. I enabled ActiveSync for a mailbox. I verified that both the Office Web Apps and ActiveSync policy is associated to the mailbox. When accessing the mailbox from two different Android phones we get the same symptoms. I'm able to authenticate/setup the mailbox to the phone, however, it never syncs. I'm able to access OWA via the same credentials successfully. I do not get any errors. It simply doesn't sync folders or any emails.