Interactive Video: "Video format not supported"

Hello forum-users. We´ve a problem with the element "interactive video" by H5P. We want to use our video production platform by the hanover university and so we tried to embed the URL of our video. In step 1 you´ll find a detailed description of the problem. After saving the video there isn´t any content but it says "video format not supported." at the video screen. Does anybody know what to do?

1. Detailed steps to reproduce the bug (exactly how and when did it happen? It happened while creating an interactive Video with inserting the URL. "https://flowcasts.uni-hannover.de/nodes/RNYnz/res1080.mp4". Then I just gave a title and saved the setting. Then the video player just is black and says "video format not supported". Our platform (Flowcasts Uni Hannover) works with other platforms without problems. 
2. Platform and version number. E.g. Drupal, Wordpress, Moodle. I tried it first with ILIAS 5.3 but also here on the homepage of h5p.org. Error was the same
3. Mobile or Desktop both
4. Browser: Chrome, Firefox, Safari etc Chrome, Firefox, Safari (more I didn´t test)
5. H5P plugin version 2.2.0
6. H5P content type and version (if a content type was used), and a sample URL or attached H5P. Interactive Video
7. Any browser console errors ---
8. Any PHP errors ---
9. Screenshots if it's a visual problem link to the object: "https://h5p.org/h5p/embed/558157"