Drill-down for Learning Summary reports not working

Hi, I am having an issue with the drill-down option in the Learning Summary reports. When I click on the graphics or on the details links, nothing happens. I tried this both in MS Edge and Google Chrome with the same result.

I also tried opening the link in a new tab/window. I just get a black screen and no data appears. Has anybody encountered this issue and can you suggest how to fix it?

Thanks

Marzia