Windows 11 Outlook account setup for legacy Exchange not working after 11/1/2025

Hi OP,

So our company had the same issue, and using outlook classic seem to have solved it for a while. But recently our users, have one by one, been affected by the same issue OP is describing. The only solution we found to solve this and force outlook to use Workmail Exchange (and not Microsoft exchange) is by following these steps:

STEP 1

[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover]

"ExcludeExplicitO365Endpoint"=dword:00000001
"ExcludeHttpsRootDomain"=dword:00000001
"DisableOffice365SimplifiedAccountCreation"=dword:00000001

Don't forget to restart your computer

STEP 2

• Clearing any associated (office,outlook,etc..) stored credentials in the window credential manager

STEP 3

• Deleting your outlook profile

STEP 4

• Start outlook, create a new profile when prompted and then add your email as a Exchange 2013 type.

NOTE:

• No issues on mobile devices (mostly IOS).
• This is a BAND AID and should not be used as a permanent fix.

• AWS support is saying this is a Microsoft issue and that they do not support 3rd party client,
• MICROSOFT support is saying it is a AWS WORKMAIL issue and that they cannot help me.

So I'm in a catch 22 situation and have not idea how to solve this.

@Microsoft, do you have any alternative solution for this?

@Anonymous Do you have any insights?

Hi Jack LeBlanc, I understand how disruptive and frustrating this issue must be especially since it affects your ability to access email and maintain productivity.

The best fix options are to use the Classic Outlook desktop client (Office 365 or Outlook 2021) since AWS WorkMail does not yet support OAuth 2.0 and the new Outlook only works with Modern Authentication configure Autodiscover correctly by adding registry keys to block fallback to Microsoft 365 and ensuring DNS points to the AWS endpoint if you must use the new Outlook set up AWS WorkMail via IMAP/SMTP for email only and for long term stability plan to migrate to Microsoft 365 or Exchange Online before April 2026 when Basic Auth is retired.

Can you confirm if you’re using the new Outlook for Windows or the classic desktop Outlook client and whether AWS WorkMail is configured via EWS or IMAP?

Best regards

Lucky Charm

The issue you're experiencing with Outlook after your mailbox has been moved to a temporary Exchange mailbox may be related to how Outlook handles connections to Exchange servers, especially in the context of legacy Exchange setups. Unfortunately, the provided context does not specifically address support for AWS WorkMail accounts in Outlook or any changes after 11/1/2025.

To troubleshoot the problem, consider the following steps:

1. Check Autodiscover Settings: Ensure that the Autodiscover settings are correctly configured for your environment, as issues with Autodiscover can lead to connection problems.
2. Recreate Outlook Profile: Although you mentioned that recreating the profile did not resolve the issue, it is often a necessary step. Make sure to completely remove the old profile before creating a new one.
3. Update Outlook: Ensure that you are using the latest version of Outlook, as updates may contain fixes for known issues.
4. Contact Support: Since this involves a specific setup with AWS WorkMail, reaching out to AWS support or checking their documentation may provide more tailored assistance regarding Outlook compatibility and setup.

For ongoing support regarding Outlook and AWS WorkMail, it would be best to refer to the official documentation from both Microsoft and AWS, as they may provide updates or changes to compatibility and support in the future.