Outlook automatically redirects

Dear @Dr Venuste Habimana,

Good day, and thank you for clearly describing the issue you’re experiencing. As a forum moderator, I genuinely wish I could directly access your account or delve into the backend systems to diagnose and fix this for you. However, our role here is limited to providing general guidance and solutions that can be applied by users. 

From my research, this is a common issue after a tenant migration or when old credentials are cached. The root cause is usually stored authentication tokens, cached data, or old profiles in Keychain Access and Outlook's local files. Please try the steps below, keeping in mind that some menu names may vary slightly depending on your macOS version.

1.Remove the old account from Outlook

• Open Outlook
• Go to Tools > Accounts.
• Select the old tenant account (or any account that appears problematic).
• Click the minus (-) button or Remove to delete it.
• Close and reopen Outlook.

2.Clear old credentials from Keychain Access

• Open Spotlight (Cmd + Space) and search for Keychain Access.
• In Keychain Access, select the login keychain from the left pane.
• Use the search box to look for entries containing:
• microsoft
• office
• outlook
• adal
• oneauth
• Your old tenant domain or email address (for example, oldcompany.onmicrosoft.com)
• Carefully delete only the Microsoft‑ or Office‑related items (right‑click > Delete).
• If nothing appears under login, also check the System keychain.
• Restart your Mac after clearing these entries.

3.Sign out of all Microsoft apps

• Open Word, Excel, or another Office app.
• Click your profile picture or initials (top‑right) and sign out of any old accounts.
• Repeat the same sign‑out step in Microsoft Teams or OneDrive, if installed.

4.Clear Outlook cache and reset local data

• In Finder, press Command + Shift + G and paste each path below one at a time, deleting the contents (not the parent folders):
• ~/Library/Group Containers/UBF8T346G9.Office/Outlook ~/Library/Caches/com.microsoft.Outlook ~/Library/Containers/com.microsoft.Outlook/Data/Library/Caches

5.Check browser redirects (if sign‑in loops occur in a browser)

If authentication redirects you to a browser, persistent cookies can also cause this behavior.

Clear cookies and site data for:

• login.microsoftonline.com
• outlook.office.com
• office.com
• microsoft.com
• Then try signing in to outlook.office.com using a private/incognito window to test.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this. Thank you for your patience and understanding. If you have any questions or need further assistance, please feel free to share them in the comments so I can continue to support you. I'm looking forward to your reply.

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