How to fix the Outlook 2016 credentials prompt error


This guide will explain how to fix the credential prompt error for Outlook for Office 365


You must have an Exchange mailbox with Sherweb. 

How to

An issue has been identified with recent builds of Outlook 2016 (version 1809, builds 10827 and higher). You may be affected if you are using Outlook 2016 and are experiencing any of the following symptoms:


  • Outlook repeatedly prompts you for your mailbox password and you have confirmed that your password is correct.
  • You get an error telling you that your mailbox has been temporarily moved on Microsoft Exchange Server.
  • You get an error telling you that 'The name could not be matched to a name in the address list'.
  • You are prompted for the credentials of another mailbox.
  • Messages you send from your mailbox appear to recipients to be from an mailbox.


Below are three ways to work around the error


Method 1: Edit the registry

Note: Incorrectly performed Registry edits can cause Windows to crash. We strongly recommend that you perform a backup of your registry before making any changes. Click here to learn how.


1. Open regedit:

 - select the Start Menu

 - type regedit in either the Run box or in the Search box

 - press Enter 

2. (HIGHLY RECOMMENDED BUT OPTIONAL) Backup your registry. Click here to learn how.

3. In the registry, navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover

4. Right-click anywhere in the right-hand column and choose NEW and then DWORD (32-bit) Value.

5. Name the entry: ExcludeExplicitO365EndPoint

6. Right-click on your new entry and select MODIFY.

7. Entry the number 1 in the Value data box, and select OK.

8. Restart your computer.

9. Recreate your Outlook profile.

10. Open Outlook and enter your email address and password when prompted.


Method 2: Update the mailbox in Credential Manager and re-build the Autodiscover.xml file 


1. Navigate to your Windows Control Panel > Credential Manager > Windows Credentials

2. Select any record(s) associated with your Exchange mailbox.

3. Click Remove just below the entry.

4. Enter %LocalAppData% in the Windows search bar and navigate to Microsoft > Outlook.

5. Delete the file(s) that ends in Autodiscover.xml. (Ex: 6b8cf067fad71d4b8b28c4f07b8b56f5 - Autodiscover.xml)


Note: Alternatively, you can rename the file(s) instead of deleting them.


6. Restart Outlook


Method 3: Revert to an earlier version of Office 2016 

Follow this Microsoft guide to learn how to revert to an earlier version of Outlook.(


If you have any questions, please browse our other support articles, or contact us directly.


Applicable to

All Exchange mailboxes using Outlook 2016