Error creating new reports using Power BI Embedded

Hi,

I've written the following code to try create a new report using Power BI Embedded:

authContext.acquireToken(window.config.endpoints.powerbiUri, function (error, token) {

                let datasetId = $("#datasetId").val();
                let embedContainer = $("#embedContainer").get(0);
           
                let models = window['powerbi-client'].models;

                let config = {
                    accessToken: token,
                    datasetId: datasetId,
                    embedUrl: "https://embedded.powerbi.com/appTokenReportEmbed"
                };

                let report = powerbi.createReport(embedContainer, config);

                report.on("saved", function (event) {
                    let msg = `report saved ${JSON.stringify(event.detail, null, "  ")} `;
                    alert(msg);
                });

                report.on("error", function (event) {
                    let msg = `error creating report saved ${JSON.stringify(event.detail, null, "  ")} `;
                    console.log(msg);
                });

            });

Everytime the code runs, an NotAuthorized error is logged however. The account that I used to test my code has admin permissions on Power BI.

error creating report saved {
  "message": "CreateReportFailed",
  "detailedMessage": null,
  "technicalDetails": {
    "requestId": "4a909e2f-4552-0433-13ed-3e9a3d2346b2"
  },
  "errorCode": "NotAuthorized"
} 

What is wrong with my security ? I'm using the "User owns data" scenario btw...

Gunther