Creating a push dataset gives a PowerBIEntityNotFound error (Issue with Service Principal only)

Hi,

I am currently investigating the BI REST API's and when I tried to create new Push DataSets from my backend service it gave me the following message:

{"error":{"code":"PowerBIEntityNotFound","pbi.error":{"code":"PowerBIEntityNotFound","parameters":{},"details":[],"exceptionCulprit":1}}}

I then tried to use the API from the API experiment website and it worked with my user. But when I tried with the Service Principal (which have admin access on my workspace), it created an error like the GroupId didn't exists or I don't know.

Here's my setup:

• Service Principal account
  • Power BI tenant settings sets on the SP (Azure portal, application settings)
• SP have full access (admin) to the Group ID or Workspace depending how you prefer to name it
• Service Principal does the get token using the MS Lib and usually work to generate token in order to view reports, get tiles, etc. (Power BI Embedded)
• Code does a call to the DataSet API to post a new dataset  (push): https://api.powerbi.com/v1.0/myorg/groups/{Group_Id}/datasets

Content of the call:

{
  "name": "MyFirstPushDs",
  "tables": [{
      "name": "MyFirstTable",
      "columns": [{
          "name": "Id",
          "dataType": "Int64"
        },{
          "name": "Name",
          "dataType": "String"
        }]
    }]
}

Is there something I am missing? 

In case you need more details, I'll add them here. I tried also to do the post from Postman and got the same error as in my application.