Mobile Menu isn´t working

Hello again ;) The mobile menu isn´t working on mobile phones. When i use the preview on pc the mobile menu works fine, but when i use a mobile phone the top menu isn´t shown. It comes a menu bellow the content, but it´s not clickable. It doesn´t do anything. My page is www.bodycontest.de. I asked friends to test the site on there mobile phones and it doesn´t work. Here a picture of the preview on pc: Here a picture of the mobile phone, without menu: Here a picture of the menu under the content, that doesn´t do anything: I don´t have any plugins for menu´s. I use the menu from the theme.