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hajar_bkg's avatar
hajar_bkg
New Member
1 year ago
Solved

Expression.Error: "The 'Authorization' header is only supported during anonymous connection

Hello Power BI / Fabric / Power Query Community, I'm working on a Dataflow Gen2 in Microsoft Fabric to connect to a REST API that requires dynamic Bearer token authentication. I'm hitting a wall wit...
data engineering
data pipeline
  • v-sgandrathi's avatar
    v-sgandrathi
    1 year ago

    Hi hajar_bkg,

    Thank you for the detailed explanation and context. You're on the right track, but you've encountered a known limitation in Fabric Dataflow Gen2.

    Dynamic Authorization headers, even with anonymous connection mode, are currently not supported in Dataflows Gen2 due to platform-level security restrictions. This is why your approach using #"Authorization" = GetToken() is causing the Expression.Error.

    The recommended solution is to shift token-based logic to a proxy service (such as an Azure Function or Power Automate flow) that manages authentication and returns clean JSON data. Your Dataflow can then connect to that service anonymously and securely.

    This limitation is acknowledged by Microsoft, and improvements may be forthcoming. For now, using a proxy service is the most reliable and scalable workaround.
    Solved: Re: API in dataflowgen2 - Microsoft Fabric Community

    I hope this helped! Feel free to ask any further questions. If this resolved your issue, please mark it as "Accept as Solution" and give us Kudos to assist others.

     

    Thank you,
    Sahasra
    Communtiy Support Team.

v-sgandrathi's avatar
v-sgandrathi
Icon for Community Support rankCommunity Support
1 year ago

Hi hajar_bkg,

 

Hope you're doing well! Just following up to see if the response we shared was helpful. If you have any further questions or need clarification, we’re here to assist.

If your issue is resolved, please consider marking the answer as Accepted and giving it a Kudos to help others in the community.

 

Thanks for being a part of the Microsoft Fabric Community!

v-sgandrathi's avatar
v-sgandrathi
Icon for Community Support rankCommunity Support
1 year ago

Hi hajar_bkg,

 

We wanted to check if you had a chance to review our last reply. Let us know if it helped or if you need more guidance, we're always happy to help further.

If the solution worked for you, please click Accept as Solution and feel free to leave a Kudos for visibility.

Looking forward to hearing from you!

  • v-sgandrathi's avatar
    v-sgandrathi
    Icon for Community Support rankCommunity Support
    1 year ago

    Hi hajar_bkg,

     

    We wanted to follow up to see if our suggestion was helpful. Please let us know how things are progressing and if you are still encountering any issues.

    If the response resolved your problem, you may mark it as the solution and give it a thumbs up to assist others in the community as well.

     

    Than you.