I keep getting an error message in outlook that says "credentials is invalid (6008)"

Question

I keep getting the following error message in the classic outlook

Correlation Id: 47c2a1c0-<removed PII>

Timestamp: 2025-11-20T14:43:22.000Z

DPTI: cb417b033df3f3b6f904ec1f5d6b0161f066bb14e6d7e52a227b35f938ce293b

Message: The credential is invalid. Unexpected sub status (6008).

Tag: 657rx

Code: 2150171662

Answer 1

Hello Charita Howard, thanks for posting this in our community.

First, verify your credentials. Make sure you are using the correct username and password. If you recently changed your password, update it in Outlook. You can also test your login through Outlook Web Access (OWA) to confirm that your credentials are valid.

Next, clear any cached credentials. On Windows, open Control Panel and go to User Accounts, then Credential Manager. Under Windows Credentials, remove any entries related to Microsoft Office or your email account. After that, restart Outlook and re-enter your credentials.

Finally, check your network connection and multi-factor authentication. Ensure you have a stable internet connection. If your account uses MFA, confirm that the app supports it and that you complete the MFA prompt.

Kind regards,

John Oli

Answer 2

The error message "The credential is invalid. Unexpected sub status (6008)" typically indicates that there is an issue with the credentials being used to connect to your Microsoft 365 account in Outlook. Here are some steps you can take to troubleshoot this issue:

1. Check Your Credentials: Ensure that you are entering the correct username and password. If you have recently changed your password, make sure to update it in Outlook.
2. Clear Cached Credentials: Sometimes, cached credentials can cause issues. You can clear these by using the Keychain Access on Mac or the Credential Manager on Windows. Delete any stored credentials related to your Microsoft account.
3. Update Outlook: Make sure that you are using the latest version of Outlook. Updates often include fixes for authentication issues.
4. Check Network Connection: Ensure that you have a stable internet connection, as connectivity issues can lead to authentication failures.
5. Contact Administrator: If you are part of an organization, there may be specific settings or policies in place. Contact your IT administrator for assistance.

If the problem persists after trying these steps, further investigation may be needed to identify any underlying issues with your account or the Outlook configuration.

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References:

• Outlook continually prompts for your password when you try to connect to Microsoft 365
• You're repeatedly prompted for credentials when using modern authentication in Outlook 2016 for Mac