Fatal error: Uncaught Error: Call to undefined function the_category_thumbnail() in /homepages/18/d29569081/htdocs/mittelmann/wp-content/themes/mmw/archive.php:16 Stack trace: #0 /homepages/18/d29569081/htdocs/mittelmann/wp-includes/template-loader.php(106): include() #1 /homepages/18/d29569081/htdocs/mittelmann/wp-blog-header.php(19): require_once('/homepages/18/d...') #2 /homepages/18/d29569081/htdocs/mittelmann/index.php(17): require('/homepages/18/d...') #3 {main} thrown in /homepages/18/d29569081/htdocs/mittelmann/wp-content/themes/mmw/archive.php on line 16