As of yet, Power BI can not query an API that uses authentication via a token added to the HTTP header. While this works when used in Power BI Desktop, the query crashes after uploading to powerbi.co...
At present it is quite difficult to implement any token-based authentication scheme from Power Query. It often requires a POST with credentials potentially visible in code. It is also quite labour-intensive.
If possible this should be generalised to cover not only the Web.Contents library function but also alternative connectors e.g. FHIR.Contents.
