Issues with Power BI report server and Basic Authentication

Hi all,

I can reproduce this issue in Power BI report server August version as well. I follow this document to set Basic authentication, when view the Power BI report( this report can render fine before set Basic authentication) in web portal, below error occur: 

When save the pbix file to report server, below error throws out: 

riccardomuti mgmeyerchrisfin You can see attached log files. Is it a known issue?

Best Regards,
Qiuyun Yu