Exchange Autodiscover after an On-Premise to Office 365 Migration

If for whatever reason you decided to do a cutover or similar migration from On-Premise Exchange to Office 365, you may find that Autodiscover can be a little sticky. The issue that I ran into is that for this environment the computers are domain joined, but we cannot immediately uninstall Exchange to remove the organization info from Active Directory. Due to this, when Outlook starts up and searches for Autodiscover, it will search for a SCP (Service Connection Point) in Active Directory, which will still be there and pointing to the wrong spot. Best case scenario this can make it take longer to start up, worst case it can end up either pointing to the wrong spot or certificate errors. The solution, though it's a bit of a hack, is to just change the connection point. I did this with ADSI Edit, note that I consider this a temporary workaround and not a permanent fix. Once you uninstall Exchange then all of this is removed from AD.

1. Open adsiedit.msc (typically from a Domain Controller)
2. Connect to the Configuration context
3. Navigate to Configuration > Services > Microsoft Exchange > (OrgName) > Administrative Groups > (Your Administrative Group Name) > Servers > (Server Name) > Protocols > Autodiscover
   
4. Edit the entry for your server and scroll down to ServiceBindingInformation
   
5. Adjust the value to reference the proper URL for your Office 365 environment. If you don't know, you can use the Autodiscover test in testconnectivity.microsoft.com to verify what your URL should be.
6. Outlook should detect it properly now, you can also verify by using the connectivity tester built into Outlook by Ctrl+Clicking the Outlook system tray icon and selecting Test E-Mail AutoConfiguration