how do i post a video?

it tells me any link is invalid?

i try the video i want. invalid.

i try a random homepage video. invalid.

how do i make it so there is a video but like where an image would be?

like this but with a play button?

my app is up to date.

edit: i know it's possible, i've seen peoples speedpaints. example: http://aminoapps.mejorapp.org/p/3ya5eq

#question