Fix for Exchange ActiveSync Failures After Migration to Exchange 2013

Monday, April 21, 2014
There’s a bug in Exchange 2013 that causes Exchange ActiveSync to fail for newly migrated users from Exchange 2010. It only affects migrated users who already have a mobile device configured, not new users (i.e., test mailboxes). This issue was discussed in the Exchange Server forums back in August 2013.

The issue occurs because the IIS application pools on the CAS 2013 servers do not automatically detect that the mailbox has been moved to Exchange 2013. When the user’s mobile device connects to CAS 2013, CAS 2013 proxies the user back to CAS 2010 which responds with an error saying the mailbox is corrupt or missing. If you run an Exchange ActiveSync test using ExRCA you will see the X-CalculatedBETarget value reported by CAS2013 is still pointing to the Exchange 2010 server. The problem usually resolves itself in 1-8 hours, depending on the Exchange 2013 build.

The workaround is to manually recycle the MSExchangeAutodiscoverAppPool and MSExchangeSyncAppPool application pools in IIS on all CAS2013 servers.

I wrote a PowerShell script for this called Recycle-AppPools.ps1:
#Use this script to recycle IIS Application Pools to overcome Exchange 2013 SP1 ActiveSync bug for migrated users

#Get all Exchange 2013 CAS servers
$CASServers = Get-ClientAccessServer | where {$_.WorkloadManagementPolicy -ne $null}

#Loop through each CAS2013 and recycle the IIS App Pools
foreach ($CAS in $CASServers) {
  Write-Host "Recycling App Pools on $CAS..."
  $appPool = Get-WmiObject -Authentication PacketPrivacy -Impersonation Impersonate -ComputerName $CAS -namespace "root/MicrosoftIISv2" -class IIsApplicationPool | Where-Object {$_.Name -eq "W3SVC/AppPools/MSExchangeAutodiscoverAppPool" }
  $appPool = Get-WmiObject -Authentication PacketPrivacy -Impersonation Impersonate -ComputerName $CAS -namespace "root/MicrosoftIISv2" -class IIsApplicationPool | Where-Object {$_.Name -eq "W3SVC/AppPools/MSExchangeSyncAppPool" }
You will need to run the script after an EAS user or batch of users have been migrated. There is no outage associated with recycling the app pools and it recycles very quickly. A fix is scheduled for Exchange 2013 CU5.