What causes Fabric Copy Activity Error 20151?

Invalid or malformed OAuth2 client credential flow settings in the linked service configuration. Incorrect token endpoint URL pointing to a non-existent or unreachable authorization server. Mismatched scopes or grant types specified in the OAuth2 configuration. Expired or rotated client secrets that have not been updated in the Fabric pipeline

How do I fix Fabric Copy Activity Error 20151?

Step 1: Open the linked service configuration in Fabric Data Factory and review all OAuth2 client credential flow settings, including token endpoint URL, client ID, client secret, scope, and grant type.. Step 2: Test the token endpoint URL independently using a tool like Postman or curl to confirm it is reachable and returning a valid response.. Step 3: Verify the error message returned in the '%errorMessage;' placeholder in pipeline logs to identify the specific OAuth2 parameter causing the failure.. Step 4: Correct any invalid settings in the linked service and re-run a test connection to confirm authentication succeeds.. Step 5: If using a Key Vault-backed secret, confirm the secret value is current and that the Fabric workspace has appropriate permissions to read from Key Vault.

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Power BI Refresh Error:
Fabric Copy Activity Error 20151

What does this error mean?

The Copy Activity failed to retrieve an access token from the configured token endpoint due to invalid OAuth2 client credential flow settings. This error indicates a misconfiguration in the authorization parameters rather than a server-side rejection.

Common causes

1Invalid or malformed OAuth2 client credential flow settings in the linked service configuration
2Incorrect token endpoint URL pointing to a non-existent or unreachable authorization server
3Mismatched scopes or grant types specified in the OAuth2 configuration
4Expired or rotated client secrets that have not been updated in the Fabric pipeline

How to fix it

1Step 1: Open the linked service configuration in Fabric Data Factory and review all OAuth2 client credential flow settings, including token endpoint URL, client ID, client secret, scope, and grant type.
2Step 2: Test the token endpoint URL independently using a tool like Postman or curl to confirm it is reachable and returning a valid response.
3Step 3: Verify the error message returned in the '%errorMessage;' placeholder in pipeline logs to identify the specific OAuth2 parameter causing the failure.
4Step 4: Correct any invalid settings in the linked service and re-run a test connection to confirm authentication succeeds.
5Step 5: If using a Key Vault-backed secret, confirm the secret value is current and that the Fabric workspace has appropriate permissions to read from Key Vault.

Frequently asked questions

What is the difference between error 20150 and error 20151?

Error 20150 occurs when the authorization server explicitly rejects the request due to an invalid client ID or client secret, returning a structured error response. Error 20151 is broader — it fires when the token request fails due to any invalid OAuth2 client credential flow setting, and the specific cause is surfaced in the '%errorMessage;' field of the pipeline error log.

Can this error occur even if the linked service test connection previously passed?

Yes. A test connection may succeed at configuration time, but subsequent token requests can fail if the client secret expires, the token endpoint changes, or scope/grant type settings are modified on the authorization server after the linked service was saved.