Sign In error

Question

I keep getting an error message when signing into Outlook. The program is trying to sign me into a tenant other than my company tenant and I cannot figure out how to stop it because I do not want to sign into the external tenant. How do I get this corrected?

Answer 1

Good day @Steve Mascaro,  

Thank you for sharing your concern.  

Just to gently clarify before we go any further, this is a user‑to‑user support forum. I don’t have the ability to access or investigate individual accounts because this is a user to user support forum. Moderators and contributors, including external Microsoft employees, do not have access to internal systems or the ability to directly take action on Microsoft product features. However, I truly hope I can help review your situation, offer some guidance, and support you in finding the right next steps as best as possible.   

To help me better understand the situation and assist you effectively, could you please share a few details such as:   

1/ What is the exact error message you receive when trying to sign in? 

2/ Does the issue occur in both Outlook on the web and the New Outlook desktop app? 

3/ Do you experience the same issue when signing in to other Office apps such as Word or Excel? 

(If possible, you may also share a screenshot showing the behavior on your side. Please ensure that any personal or sensitive information is hidden or blurred before sharing.) 

This will help me better understand the context and provide more targeted support. Any additional information will help me better understand and support you.    

In the meantime, you can try this workaround to verify the issue: 

• Clear browser cache 

This can help determine whether the issue is related to the app or the mailbox experience. 

Open a web browser, then go to the browser settings and clear browsing data. Set the time range to "All time" to avoid issues caused by outdated cache.     

Go to https://www.office.com and sign in your work account.    

Once signed in, select Apps > Choose Outlook.  

Additionally, you can open an InPrivate or Incognito browser and follow the same steps above. Then, select other Office apps such as Word, Excel, or OneDrive to verify the behavior. 

Since the issue may have multiple causes and more details are needed, further information will help in providing more accurate troubleshooting steps. I would appreciate any additional details you can share. 

Looking forward to your response so I can assist you more effectively. Thank you very much for your understanding and your cooperation.      

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Answer 2

For Outlook on the web, this usually happens when the browser is holding on to a previous sign-in or cached tenant information. Use these steps to force Outlook to use the correct (company) tenant:

1. Sign out of Outlook on the web completely:
   • In Outlook on the web, select Account manager (your picture/initials in the top-right).
   • Select Sign out.
2. Clear cached sign-in and try again:
   • Close all Outlook on the web tabs.
   • Clear the browser cache (or open a new InPrivate/Incognito window).
   • Browse back to the Outlook on the web sign-in page.
   • When prompted, enter the company work or school account only.
   • On the sign-in page, clear the Keep me signed in checkbox so the browser does not automatically reuse the wrong tenant in the future.
3. If the wrong tenant is still used or the password is rejected:
   • If the account is a work or school account and the password is not working, use the self-service password reset page if allowed by the admin: https://passwordreset.microsoftonline.com/ (or https://passwordreset.activedirectory.windowsazure.cn/ for the China cloud), then sign in again with the company account.
   • If self-service reset is not allowed, contact the company Microsoft 365 admin and ask them to verify the account and tenant configuration.

If the mailbox has been disabled in the company tenant (for example, if the account was recently changed or terminated), Outlook on the web can also fail to load correctly even though sign-in to Microsoft 365 succeeds. In that case, the Microsoft 365 tenant administrator must check whether the mailbox is disabled and re-enable it before Outlook on the web will open the correct mailbox.

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References:

• How to sign in to Outlook on the web
• Not able to have access to my email ! - Microsoft Q&A