Problem with the platform

Hello,

I have this problem with the platform: Video in Lesson 5 of Mobile Marketing is not loaded. I provide a screenshot of it attached. Also, all introductory text, such as 5.1 Mobile Marketing Foundations Mobile Advertising that I attach also, show a blank page with no text in it. I have already cleared cache memory and cookies in chrome, I have switched to firefox but the problem remains.

Any help would be valuable.

Thanks,
Stella