Once in a while we hear this, and so far every time it has been because parents and students are trying to log in to the video site from the wrong website. Parents and students must log in from LivresVideo.net  and not from LecturEnfant.net  (teacher access only, different username and password). Please be sure to check with parents that they are logging in from the video site LivresVideo.net. As all students in a class share the same username and password, it is extremely unlikely that it works for some but not for others.