Active sync not working after 2012 r2 servers promoted to domain controllers

Built two new virtual 2012 R2 servers, then promoted them both to domain controllers.  My 2003 SP2 Domain Controllers are still up an running normally on my network.  All went perfect last night, then this AM we noticed we were not getting email pushed down to our iPhones.  Some users are getting a cannot connect to server message and some users such as myself are just not getting the new emails.  
We have a 2003 domain, 2 - 2003 domain controllers (DNS, AD), 1 - 2003 Exchange server, 1 - 2003 OWA Exchange server (running in a DMZ).  We use our OWA website to connect the iPhones to the email.  I can log into OWA via IE just fine, it is just no email on the iPhones.

I have been searching this site for answers and am not finding the info I need, so decided to ask here.   All our email is functioning properly, just active sync is not.  Any suggestions?  Thanks.
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Will SzymkowskiSenior Solution ArchitectCommented:
You will need to either demote your 2012 DC's then upgrade Exchange to a newer verion. Exchange 2003 is NOT compatible with 2012 domain controllers.

Also see another MVP post.


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SherryPowersAuthor Commented:
Hi Will,
Is this true even though I still have my 2003 domain controllers up and running?  I thought as long as the 2003 domain controllers were left up I would be ok.  All my email is functioning correctly, just the active sync from OWA to the iPhones is not working...  Thanks
Will SzymkowskiSenior Solution ArchitectCommented:
I cannot say for sure that this is the case however, I know that Exchange 2003 is not supported with 2012 DC's and as you are having issues means my theory is probably correct.

Just because Microsoft does not "support" this does not mean some features will NOT possibly work. as you have changed this and Exchange broke the next morning makes me believe that it is due to 2012 DC's.

SherryPowersAuthor Commented:
We actually decided to do an upgrade to Exchange 2010 ahead of our originally planned schedule.  

We did not demote the 2012 R2 DCs.  We just upgraded to Exchange 2010 then moved all the mailboxes over from Exchange 2003.  Once this was completed, all iPhone email problems were fixed.

During all this, our regular email continued to function normally.  Just the Active Sync was broken.

Thank you for your input Will.

SherryPowersAuthor Commented:
I am selecting my own comment because we did not demote our newly created and promoted Domain Controllers as Will suggested in his initial comment.  We only moved all the Exchange 2003 mailboxes over to the new Exchange 2010 server.  I don't want someone to think they must demote the DCs to fix this problem...  Sherry
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