Since yesterday I am trying to get an embedded video working on a website. First my browser told me, that it just can't display the video. After updating the link, my browser tells me it is not allowed to open the link to protect my security. I came across CORS (Cross-Origin Resource Sharing) and enabled that in the CMS, ignore X-Frame-Options Header and fiddled with the .htaccess file (see here) which crashed an entire website (luckily I tried on an unimportant site first).