Improvements needed – Simplilearn: Online Learning Review

I have the iPhone 6S and the some of the videos do no display anything. I can hear the gentleman speaking but the display isn't there. For example he states "click on each of the tabs to read further". It's blank. I don't have any options. I can press pause for the audio or reply it but that's it. Not sure what's going with this app. I'm not impressed.
Review by Ladyb2278 on Simplilearn: Online Learning.