Using classic Outlook for Windows in business environments
Good day Z,
Just to gently clarify before going any further, this forum is separate from Microsoft Support. Forum users, moderators and Microsoft external staff cannot access user accounts or directly escalate cases.
Currently, I checked the information currently available and didn't find any reported service incident related to this issue, nor any announcement that Microsoft has blocked work accounts from using Classic Outlook.
Since the issue only affects Classic Outlook, please try the following:
Step 1: Repair Microsoft 365 apps
Close all Office applications.
Open Control Panel > Programs > Programs and Features.
Select your Microsoft 365 installation and choose Change.
Run Online Repair.
Restart Windows, then try adding the account again.
Step 2: Create a new Outlook profile
Close Outlook.
Open Control Panel > Search and open Mail > Show Profiles.
Select Add and create a new profile.
Sign in with your work account.
Set the new profile as the default profile > Apply > OK and open Outlook.
Step 3: Contact Microsoft Support
Since you can access the Microsoft 365 admin center, if your account has the required administrative permissions, you can create a support request directly with Microsoft through the Microsoft 365 admin center > Support > Help & Support for further investigation.
Note: If you don't see the support option or don't have sufficient administrative permissions, please contact your Global Administrator for assistance. In case you do not know who is your Global admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support
A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis.
As a forum user, I can provide troubleshooting guidance based on public documentation, and I don't have access to backend tools. For this reason, contacting Microsoft Support is the best next step if the issue continues after completing the steps above.
If you have any questions or need further support, please don’t hesitate to reach out at any time.
Thank you for your patience and understanding.
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