Why video is not displaying?

Question

I used iframe to display video. But it is not working why?
https://code.sololearn.com/WdgFvPX61FUi/?ref=app

Answer 1

This Sololearn lesson maybe helpful :
https://www.sololearn.com/learn/338/?ref=app

Answer 2

https://code.sololearn.com/Wgjduq1I87gR/?ref=app see the iframe in this code