Problem with video dailymotion are not responsive

I saw that if you load a video of this type Daylimotion http://www.roygigolo.com/blog/ospitate-tv/le-iene-e-il-gigolo-che-non-riesce-a-pagare-le-tasse
however, if it is not responsive load a video from youtube that's responsive, where am I wrong?

thanks a lot