What causes AADSTS501491?

Malformed or invalid token/credential value. Multi-factor authentication required

How do I fix AADSTS501491?

Step 1: Check the Azure AD error lookup at login.microsoftonline.com/error for this code. Step 2: Review your application's authentication configuration in Azure portal. Step 3: Contact your Azure AD administrator if the issue persists

High severityauthentication

Power BI Refresh Error:
AADSTS501491

What does this error mean?

Invalid size of Code_Challenge parameter.

Common causes

1Malformed or invalid token/credential value
2Multi-factor authentication required

How to fix it

1Step 1: Check the Azure AD error lookup at login.microsoftonline.com/error for this code
2Step 2: Review your application's authentication configuration in Azure portal
3Step 3: Contact your Azure AD administrator if the issue persists

Frequently asked questions

What does AADSTS501491 mean?

Invalid size of Code_Challenge parameter.

How do I fix this error?

Check your application registration, token configuration, and user permissions in the Azure portal. Review Conditional Access policies if the error is policy-related.