"Unable to open document" message when attempting to open report in Power BI Desktop from PBIRS

[pbiwork]

Hello, we are using the March 2018 version of Power BI Report Server and Power BI Desktop.  When we log in to PBIRS and click the "Edit in Power BI Desktop" option for a report, Power BI Desktop opens and presents this message: "Unable to open document  Unexpected error encountered". 

Any idea what might be causing this?

[pbidashboard]

I have exactly same problem, after implemented custom security.

Wondering what account Power BI Desktop is using to log on to Report Server?