Difficult to answer since I have to rely on the Translate functionality. What do you mean by 'video export'? Is this publishing to HTML5 or do you indeed publish to MP4 (which is video)? Or is it about embedded videos in a normal cptx project which you publish? Red mostly means that something is wrong with the format of the graphic or the video. If you published to HTML5, did you upload the course to a webserver? Which browser did you use?