embedded vimeo not loading

I've embedded a lot of videos in my moodle page. Some of them are not loading at all or talkig forever to load. Sorry for posting a stupid question, but I just don't know what to do. Could there be something in the iframe that is causing problems: <center> <div class="video-max-size"> <div class="embed-responsive embed-responsive-16by9"> <iframe src="http://player.vimeo.com/video/116054472?title=0&byline=0&portrait=0" frameborder="0" width="500" height="281"></iframe> </div> </div> </center> Any tip would be very appreciated!