Microsoft released an update (KB 2974308) today to address the issue where integrating Windows Server Essentials 2012 R2 with Microsoft Office 365 or Windows Azure Active Directory is blocked when you are in a multiple domain controller environment.
Until now, you could only integrate Windows Server Essentials with O365/Azure AD in a single domain controller environment.
Attempting to run the integration in a multiple DC environment would fail:
I’m proud of the work that our MVP group did in identifying this issue soon after the release of Essentials 2012 R2 last year.