1. to debug all courses page in app please share your site url ,admin credentials and a valid FTP credentials to check this issue at your end in private reply .
for videos please make sure that unit type it set to ” video ” use iframevideo shortcode it will render in app : http://prntscr.com/k2ewg6
use the iframevideo shortcode like this :
[iframevideo]iframe-code[/iframevideo]
example :
[iframevideo]<iframe src="https://www.youtube.com/embed/MFtX9ussRKk" width="560" height="315" frameborder="0" allowfullscreen=""></iframe>[/iframevideo]