Post mailbox migration Exchange 2013 ActiveSync failures

There is an issue with Exchange 2013 first reported around the CU2 release date and is still an issue as of CU8.  The issue presents itself to existing users with an ActiveSynced device after mailbox migration.


  • Users experience an outage on mobile device for up to 16 hours, but typically it resolves itself within 8 hours.
  • Not all mailboxes are affected.
  • Not all devices utilizing the same mailbox are affected.  For instance, I had an iPhone and an iPad on the same account; the iPhone experienced no issues, but the iPad failed to connect.
  • Email can be sent from a device but not received.
  • Connection attempts to the server are rejected initially with a 130 – Access Denied error when viewing MDM logs or when utilizing tools such as LemonJar’s iOS Console utility.  Errors will eventually turn to IIS 403 – Forbidden errors after approximately 30 minutes of attempted connections.
  • EAS logs indicate that a user device is still being proxied to the server they were migrated from.
  • Issues appears to be completely intermittent in nature.

This is a result of the IIS application pools on the 2013 CAS not being made aware that the mailbox has moved.  The issue itself is easy enough to resolve by recycling IIS application pools: MSExchangeAutodiscoverAppPool and MSExchangeSyncAppPool on the 2013 CAS.  It may take up to 15 minutes after recycling the application pools for mail to begin to flow normally.

While researching this issue I came across an article by Jeff Guillet who has additional information and a script available on

Leave a comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.