Index.html files present but fail to load?

Hi folks,

I have a number of courses that have content designed in Articulate, that is then imported into Brightspace. We have never had this issue before but now when I click a module with that content, the initial slide appears, and there's a button to start the lesson.

You click start lesson, and blank screen.

And it's occurring in every course and module, including courses from past years.

Any ideas?

Thank you,