Installed the latest (dev) versions of media/file entity/you tube/soundcloud/vimeo.
Always get: http://xxxxxxxxxx konnte nicht hinzugefügt werden. Only the following types of files are allowed to be uploaded: video, image, audio, document.
Added video/vimeo and video/youtube to mimetypes but no changes.
Edit: I upgraded from media 7.1. It worked there but I needed the newer version for hiding some tabs.