My scenario, One week ago,
Exchange 2003 facing internet, internal users, via Outlook anywhere and ActiveSync, also 28 users on Exchange 2003, and one user in office 365 cloud (midsize business) without AD integration.
I wanted to migrate all my 28 users to Office 365 cloud.
What I did, followed too many websites tutorials and came to this:
I installed a new Windows 2012 standard server, installed Exchange 2010 (I want to uninstall it latter, don´t want to pay a license if I am going to pay for 30 office 365 licenses), migrated all roles for AD from Windows 2003 to Windows 2012, managed to make Exchange 2010 coexists with Exchange 2003, now, I have Windows 2012 facing the internet and my old server in a non-facing internet...
Mail will flow normally, people can connect to their 2003 mailboxes through Exchange 2010, same as people on Outlook anywhere and ActiveSync.
I moved one mailbox from exchange 2003 to exchange 2010, everything was normal.
Then I installed DirSync and sent my AD to Office 365, all users appeared on my portal, everyone appeared with @office365domain.onmicrosoft.com, when I try to migrate users using the portal of Exchange administration, remote move (compatible with Exchange 2010), I choose the user, because I don´t have an autodiscover certificate, I do not have the subdomain created, after clicking next, prompt me for the admin users and password, then it gives me an error that they cannot find the configuration of my server.... please enter FQDN of Exchange server (MRS).... here I enter the external url of my Exchange, and I get an error that it cannot connect.. so I cannot migrate any mailboxes!!!, I am trying to use IMAP to migrate…. Cant!!!!!
And Office 365 will not create a mailbox until it´s migrated!!
What should I do?