Migrating users from an Exchange 2010 SBS server to Exchange 2016 I noticed that after one mailbox had completed the user was prompted to quit and restart outlook. But after the user did that nothing happened and their profile was still connected to the Exchange 2010 server. I tried to create a new profile but it wouldn’t complete giving me the infamous message

“Action cannot be completed. The connection to microsoft exchange is unavailable”

After double and triple checking my URL’s SCPs etc… I found that recycling theĀ “MSExchangeAutodiscoverAppPool” service on the Exchange 2016 Server resolved the problem.

  1. Open IIS on the Exchange 2016 Server
  2. Click on Application Pools
  3. Right Click on “MSExchangeAutodiscoverAppPool”
  4. Choose Recycle

You can either recycle the app pool each time you migrate a mailbox or check out the MS KB that guides you through setting it up to recycle every minute.

https://www.iis.net/configreference/system.applicationhost/applicationpools/add/recycling