Authentication failed for data source – Invalid or expired credentials for a data source connection

The “Authentication Failed for Data Source” error in Power Automate occurs when a flow cannot access a data source due to invalid, expired, or missing credentials.

Error Message:
"Authentication failed for data source – Invalid or expired credentials for a data source connection."

This issue can be caused by:

• Expired credentials or OAuth tokens
• Incorrect username, password, or API key
• Insufficient permissions for the connected account
• Multi-factor authentication (MFA) blocking automated access
• Changes in security policies or service settings

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2. Common Causes and Fixes

Cause	Description	Fix
Expired Credentials	OAuth tokens or passwords have expired.	Re-authenticate the connection in Power Automate.
Invalid Credentials	The username, password, or API key is incorrect.	Verify login details and update stored credentials.
Insufficient Permissions	The user account does not have the required access level.	Grant necessary permissions in the data source.
MFA Blocking Access	Multi-factor authentication (MFA) requires manual approval.	Use an App Password or Service Account to bypass MFA.
Service Policy Changes	Organization security policies may block access.	Check with IT Admins for updated authentication policies.

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3. Step-by-Step Troubleshooting Guide

Step 1: Re-authenticate the Connection

If your authentication token has expired, reconnect the data source.

Steps to fix:

1. Open Power Automate.
2. Navigate to Data → Connections.
3. Locate the failing connection and click Fix Connection or Edit Connection.
4. Re-enter credentials and authenticate again.

Example Fix:

• If a SharePoint connection fails, re-enter your Microsoft 365 credentials and save the connection.

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Step 2: Verify Login Credentials

Incorrect credentials can prevent Power Automate from connecting to a data source.

Steps to fix:

1. Try logging into the data source directly (e.g., SharePoint, SQL Server, OneDrive).
2. If login fails, reset the username or password.
3. Update Power Automate with the correct credentials.

Example Fix:

• If an SQL Server connection fails, verify the username and password in SQL Management Studio.

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Step 3: Check Permissions for the Connected Account

If the account lacks access to the data source, authentication will fail.

Steps to fix:

1. Open the data source settings (e.g., SharePoint, SQL, Dataverse).
2. Ensure the connected user has read/write permissions.
3. If needed, ask an admin to grant the required access.

Example Fix:

• If a Power Automate flow fails to access a SharePoint list, check if the user has at least “Contribute” permissions.

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Step 4: Handle Multi-Factor Authentication (MFA) Issues

Some services require MFA, which can block automated authentication.

Ways to fix:

• Use an App Password instead of the regular password.
• Set up a Service Account that does not require MFA.

Example Fix:

• If connecting to Exchange Online, create an App Password in Microsoft 365 Security & Compliance Center.

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Step 5: Check Organizational Security Policies

Company-wide security policies may restrict authentication methods.

Steps to fix:

1. Contact your IT Administrator.
2. Ask if Conditional Access Policies or Security Restrictions have changed.
3. If needed, request an exemption for Power Automate connections.

Example Fix:

• If a Microsoft Dataverse connector fails, check if new Azure AD security policies block third-party logins.

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Step 6: Recreate the Connection in Power Automate

If re-authenticating does not work, delete and re-add the connection.

Steps to fix:

1. Open Power Automate.
2. Navigate to Data → Connections.
3. Delete the failing connection.
4. Create a new connection and enter credentials again.

Example Fix:

• If an Azure Blob Storage connection fails, remove the old connection and reconfigure it from scratch.