Fatal error: Uncaught Error: Call to undefined function kalium_is_custom_header() in /customers/0/e/8/photo-art.be/httpd.www/wp-content/themes/kalium-child/tpls/header-main.php:107 Stack trace: #0 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/template.php(725): require() #1 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/template.php(672): load_template('/customers/0/e/...', false) #2 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/general-template.php(168): locate_template(Array, true, false) #3 /customers/0/e/8/photo-art.be/httpd.www/wp-content/themes/kalium/includes/functions/template/header-template-functions.php(25): get_template_part('tpls/header-mai...') #4 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/class-wp-hook.php(287): kalium_header_display('') #5 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters('', Array) #6 /customers/0/e/8/photo-art.be/httpd.www/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #7 /customers/0/e/8/photo-art.be/http in /customers/0/e/8/photo-art.be/httpd.www/wp-content/themes/kalium-child/tpls/header-main.php on line 107