Lightbox effect does not work on video

Hello.

I installed Responsive Lightbox plugin and enabled it then I choose to enable effect on Youtube links.
But id does not work.

I write a post, paste a link like https://www.youtube.com/watch?xxxx

Write editor displays the video, the published post also displays the video but no lightbox effect.

You can see it here with 2 videos : http://www.parigotmanchot.fr/2016/06/23/haptonomie-concept-affectivite-grossesse/

Any idea ?

Thanks.

https://wordpress.org/plugins/responsive-lightbox/