Outlook 2016: Microsoft account association prevents connecting to mailbox after update

We have found that a recent update (October) to Microsoft Outlook 2016 included in Office 365 package, has caused Outlook to insist that IF your email address is linked to a Microsoft account then you must be trying to connect to a Microsoft hosted mailbox instead of one hosted by your service provider or your company. For example we have clients who have setup a Microsoft account with their email address (mailbox hosted elsewhere) to use the Microsoft app store, Skype, Volume Licensing Service Center etc. After the October update Outlook has problems connecting to their original mailbox or setting it up in the first place.

The reason for this is that October update changed the way Microsoft Outlook handdles the Exchange Autodiscover. In these cases, Outlook is attempting to redirect to Microsoft’s own Office 365 servers, due to the user’s email address being associated to a Microsoft account. To correct this situation, you have two choises. You either have to remove the association between your Hosted Exchange email address and the Microsoft account, or put a registry key in place to tell Outlook NOT to look for Autodiscover settings from Microsoft servers if it has the email address is associated with Microsoft account. We show you how to do both of them.

SYMPTOMS AND VERIFICATION OF THE MICROSOFT ACCOUNT CONFLICT

The following issues are indications of Microsoft account conflicts:

• Warning message “Your mailbox has been temporarily moved to Microsoft Exchange server.”
• Warning message “Cannot start Microsoft Office Outlook. Cannot open the Outlook Window.”
• A password prompt appears when you open Outlook
• Your Outlook shows your email address as outlook_**@outlook.com
• You receive bounce messages for outlook_**@outlook.com
• Users with full access to other mailboxes are prompted for a password
• Outlook Autodiscover resolves to https://outlook.office365.com/autodiscover/autodiscover.xml first

To verify that the email address is associated with a Microsoft account, navigate to https://login.live.com/, type in the affected email address, and click Next. If you receive the warning stating “That Microsoft account doesn’t exist. Enter a different account or get a new one.”, then the email address is not associated to a Microsoft account and this article doesn’t apply. If you are prompted to enter your password, your email address is set as the primary alias for your Microsoft account.

SOLUTION 1: Remove the association from Microsoft account

Remove the association

1. Sign in to https://login.live.com/ with your Microsoft account. (Warning: If you use the Forgot password option, do not select “Click here to remove your email address from that account” in the password reset email. You might loose your Microsoft Account.)
2. Select “Your info” from the upper-left corner of the page.
3. Select “Manage your sign-in email or phone number”.
4. You might be asked to verify your identity. Please, select the preferred method and proceed with verification.
5. Locate the affected email address under the Account alias section.
6. If the affected email address is the only one, select “Add email” and proceed with adding another email address so that you can still sign in to your Microsoft Account later.
7. After you have a secondary email address to the account, select “Make Primary”. If you are asked to verify ownership of the new email address, proceed with sending the email address an ownership verification email.
8. After you have successfully changed the primary alias, select “Remove” next to the affected email address to remove it from your Microsoft account.

After your email address is no longer associated with your Microsoft account, restart your device and open Outlook. You might need to recreate your Outlook profile.

For more information about how Outlook 2016 implements Autodiscover, see Outlook 2016 Implementation of Autodiscover.

SOLUTION 2: Add a registry key to tell Outlook NOT to look for Autodiscover settings from Microsoft servers

The fix is to put a registry key in place to tell Microsoft NOT to exclusively look to Microsoft servers for Autodiscover settings if it has the email address listed on its systems. Here’s how:

1. Make backup of your Windows Registry.
2. Open up the registry by going to Start > type “regedit” and hit enter.
3. Locate the following key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover.
4. Add the DWORD “ExcludeExplicitO365Endpoint” (without the quotation marks) and give it a hex value of 1.

Now restart the machine and recreate the Outlook profile.

NOTES:

Please note, that either of the solutions won’t work if you have errors in you Autodiscover implementation. Please check it with Microsoft Remote Connectivity Analyzer or the Outlook integrated “Test E-mail AutoConfiguration…”. The later can be found by starting the Outlook and, while holding Ctrl down in you keyboard, right-click the Outlook Tray icon. Sometimes the Autodiscover process can stop with faulty configuration of your FQD HTTPS settings.