When I open this lesson the following text pops up and when I press ok, it takes me back to the starting page. I am using google chrome and Windows 10. Also the problem seems to be with this specific lesson La vida occulta de Fidel Castro (course) Nicaragua, la otra revolucion de Fidel 2/3 (lesson).
Edit: I didin’t manage to get the croped picture attached but the text in the box between forum and the spanish flag says: There was an error opening this lesson. We have been notified and will investigate this issue. You will be redirected to the home page where you can try opening another lesson.