ActiveSync stops working after migrating from Exchange 2007 to Exchange 2013

Question

We have started the migration from Exchange 2007 to Exchange 2013. We've followed best practices and everything is working great except ActiveSync. I've performed Exchange migrations in the past so this is nothing new for me. I've also been referring to
a great guide which has been a big help,
http://www.msexchange.org/articles-tutorials/exchange-server-2013/migration-deployment/planning-and-migrating-small-organization-exchange-2007-2013-part1.html.
Once a user is migrated from Exchange 2007 to 2013, ActiveSync stops working properly. Email can be pulled to the device (Nokia Lumia 625 running Windows Phone 8) by performing a manual sync. But DirectPush is not working. The strange part is it's not affecting
everyone who's been migrated. Anyone who is still on Exchange 2007 is not affected.
At first I thought it was our wildcard certificate. 99% of our users are running Outlook 2013 on Windows 7 or higher but we do have a few terminal servers still running Outlook 2010. Outlook 2010 was giving us certificate errors. I realized it was the wildcard
certificate. Rather than making changes to the OutlookProvider I simply obtained a new SAN certificate. Although that resolved the issues for Outlook 2010 users, ActiveSync was still a problem.
Rebooting the phones and removing the email account from the user's device and re-adding it didn't resolve the issue either.
Then I performed an iisreset on the CAS server. This didn't help either. I didn't know it at the time, but I was getting closer...
I tried using the cmdlet Test-ActiveSyncConnectivity but it gave me the following error:
WARNING: Test user 'extest_0d9a45b025374' isn't accessible, so this cmdlet won't be able to test Client Access server
connectivity.
Could not find or sign in with user DOMAIN.com\extest_0d9a45b025374. If this task is being run without
credentials, sign in as a Domain Administrator, and then run Scripts\new-TestCasConnectivityUser.ps1 to verify that
the user exists on Mailbox server EX02.DOMAIN.COM
I started reviewing how Exchange 2013 proxied information from the CAS to the mailbox server and realized the issue may in fact be on the mailbox server.
I performed an iisreset on the mailbox server and all of a sudden ActiveSync started working again. Awesome!
I can't explain why. The only thing I can assume is when some users were migrated from 2007 to 2013 something wasn't being triggered on the Exchange 2013 side. Resetting IIS resolved the issue. I guess I'll have to do an IIS reset after I perform a batch
of migrations. Disabling ActiveSync and re-enabling it for the affected users didn't help - only the IISRESET resolved the issue.
If anyone has any information as to why this happens, please chime in. Also, if anyone knows why I can't run the Test-ActiveSyncConnectivity cmdlet, I'd appreciate the help.
Thanks.

Answer 1

Hi,
In Exchange 2013, the Public Folder is changed to Public Folder mailbox instead of Public Folder in Exchange 2007 database.
Due to the changes in how public folders are stored, legacy Exchange mailboxes are unable to access the public folder hierarchy on Exchange 2013 servers. However, user mailboxes on Exchange 2013 servers or Exchange Online can connect to legacy
public folders. Exchange 2013 public folders and legacy public folders can’t exist in your Exchange organization simultaneously. This effectively means that
there’s no coexistence between versions.
For this reason, it’s recommended that prior to migrating your public folders, you should
first migrate your all legacy mailboxes to Exchange 2013. For more information about migrating public folder from previous versions, please refer to:
http://technet.microsoft.com/en-us/library/jj150486(v=exchg.150).aspx
(Please note the What do you need to know before you begin part in this link)
Regards,
Winnie Liang
TechNet Community Support