Video only as image

Hello,
I have the custom twitter feed on my website, and I want to show videos in the lightbox overlay, which I have retweeted.
For some reason it only shows some videos with the play button on the thumbnail. Some videos are only shown as a jpg.
Why is that so?
Here is a link to a video which is only shown as an image:

?? Let's have a closer look at how @quickstepteam perfectly led @FndoGaviria to his first win on Le Tour ! ??
?? Superbe travail de @quickstepteam qui a véritablement dépose Fernando Gaviria dans un fauteuil à 200m de la ligne ! ??#TDF2018 pic.twitter.com/KxeGqfHZfD

— Tour de France? (@LeTour) July 7, 2018

Thanks in advance,

N. Smith

The page I need help with: [log in to see the link]