We’ve set-up the On-premise Power BI Report Server. I published a Power BI (pbix) report to the Power BI Report Server; the report is pulling data from a multi-dimensional SSAS data model. We’ve tested and the report outputs successfully on our local copy of Power BI Desktop optimized for Report Server. When we publish and run the report from the power bi report server, we get the "oops, something went wrong Unable to load report" error message when running the report. The Data source test connection looks good.
I checked the "RSPowerBI..." log files. I'm getting the error: "|ERROR|19|Error occurred while retrieving pbix file from Portal. Status Code: Forbidden, Message: |".
I got the same issue and I found that my NTID don't have Browser access type checked on the sercuity page. Your administrator can do this and also make sure that your user name or the service account belongs to the SSRS server group on your network. Along with these the user account should have access to the cube.
The error you are getting looks like a permissions issue trying to retrieve the report from the Report Server catalog. Can you check to security settings on the Report and make sure the user that is trying to access the report has at least the Browser role set?