'Message': 'Internal error MwcTokenValidationException.', 'Source': 15, 'ErrorCode': 0

Hi cesarniyo ,

In Microsoft Fabric, when you run a job manually, it executes under your user identity, and Fabric automatically provides a valid workspace token. That’s why MLflow works in that case.

When the job is triggered via a pipeline, it runs under the pipeline execution identity (usually the workspace managed identity or a configured service principal), not your user account. This identity must be explicitly granted Contributor or higher access to the Fabric workspace. If it isn’t, the Fabric MLflow gateway cannot validate the token and throws MwcTokenValidationException.

To resolve your issue, please check the workspace access and ensure the pipeline’s execution identity has Contributor/Admin permissions. No code changes or manual token handling are required.

Once permissions are updated, MLflow calls from the pipeline should work the same way as manual runs.

Thank you.