social media icons won´t show in frontend

Hi, I added social media buttons in the footer area. They are displayed in the backend in the life preview but not in the frontend. What shall I do? I checked the links and they are all right.. they are working out of the backend. URL: http://new.aquariumcomputer.com/de/wp-admin/customize.php?return=%2Fde%2Fwp-admin%2Fwidgets.php Thanks for your help