Youtube and Vimeo videos don′t show up

since a few updates videos from youtube and vimeo are not shown correctly in the lightbox/fancybox. you can see it here: https://www.paragliding-academy.com/gleitschirm-sicherheitstraining/

scroll down and click on “VIDEO GLEITSCHIRM SICHERHEITSTRAINING” the windows opens but no video shown.

thanks for your help,

chris