Keeps signing me out

Remove the saved school-account credentials from Windows Credential Manager, restart Windows, and then sign in again using your full school email address.

Remove the stored credentials

Since clearing the browser cache and using Incognito did not help, avoid repeating those steps:

1. Press Windows + R.
2. Enter control, and press Enter.
3. Open User Accounts → Credential Manager → Windows Credentials.
4. Expand entries associated with your school account, Microsoft 365, Office, Outlook, or your school’s sign-in domain.
5. Remove only entries tied to the affected school account.
6. Restart the computer.
7. Open the school’s normal Microsoft 365 or email link and enter the complete school email address rather than selecting a remembered account.

This is the next user-side step recommended for a closely matching school-account login/logout loop after browser-cache troubleshooting has failed.^1^

Removing credentials can sign that school account out of Office and Outlook, so expect to authenticate again.

Run one discriminating test

Try signing in from another device or while connected to a different network, such as a mobile hotspot.

• Works elsewhere: the problem is likely limited to the original Windows device, its stored credentials, or its network.
• Fails everywhere: contact the school’s IT help desk because the school controls the account, MFA configuration, Conditional Access policies, and Microsoft 365 access.

Avoid making many repeated attempts. Microsoft Entra can temporarily restrict further attempts when it detects unusual or repetitive sign-in activity.^2^

What to ask school IT to check

Provide the approximate time of the latest attempt and explain:

“MFA verification succeeds in Outlook, but the browser immediately returns to ‘Pick your account.’ Clearing the browser cache and using Incognito made no difference.”

Ask IT to:

1. Open Microsoft Entra admin center → Entra ID → Monitoring & health → Sign-in logs.
2. Filter by your username, the affected application, and Status: Failure.
3. Open the matching event and review:
   • Failure reason
   • Additional details
   • Sign-in error code
   • Correlation ID

The failure details determine whether this is an incomplete sign-in, expired session, Conditional Access issue, account restriction, or MFA problem.^3^

Depending on the logged failure, an authorized school administrator can then use Entra ID → Users → your account → Authentication methods to:

• Revoke sessions if stale refresh tokens are maintaining the loop.
• Require re-register MFA only if the logs indicate an MFA registration or authentication-method problem.

Re-registering MFA deletes registered Authenticator, phone, and software OATH methods and requires them to be configured again, so it should not be the first action when your verification code is already being accepted.^4^

IT should also verify that the account is enabled, not locked, has the required Microsoft 365 license, and is not being blocked by Conditional Access.^5^

References

1. Outlook Mail Login/Logout loop - Microsoft Q&A
2. Common problems with two-step verification for a work or school account
3. How to troubleshoot Microsoft Entra sign-in errors
4. Manage user authentication methods for Microsoft Entra multifactor authentication
5. Problems signing in to a Microsoft application