Embed report in report

Hi, I know this topic isnt something entirely know. But I did my share of reading and tried everything.

My situation is following - company uses report server, but different units dont cooperate well - so I need way to glue reports together without combining data itself. Embeding seemd like a smart way to do it BUT when I used htmlViewer visual and inserted iframe code consulting https://docs.microsoft.com/en-us/power-bi/report-server/quickstart-embed , all I get is:

Am I trying to do something thats not possible or is it bad configuration of our report server? Thanks!