Unable to combine data error in Service with Web.Contents API Call on Dataflow result

Hi freidav1984,
Thank you for reaching to the Fabric Community.
This error usually shows up in Power BI Service because it’s stricter about dynamic data sources than Desktop. When a query builds a Web.Contents URL based on another query, like pulling values from Excel - the service can see it as combining multiple sources and blocks the refresh. A good way around this is to use a static base URL with RelativePath or Query parameters instead of fully dynamic URLs, and make sure the privacy levels for both your Excel file and API match, ideally set to None or Organizational. You can also stage your Excel data separately or move your API logic into a Dataflow to break these cross-query dependencies.

Also, check that both your Excel source and API are registered on the same gateway and that credentials are consistent in Power BI Service. If this still doesn’t solve it, sharing a masked version of your query in the forum can help others troubleshoot, or you might need to submit a support ticket for a closer look. These steps usually fix most dynamic source refresh issues in Power BI Service.