Warning: Trying to access array offset on null in /var/www/app/public/autor.php on line 9

Fatal error: Uncaught TypeError: getBlogPostsByAuthor(): Argument #2 ($authorName) must be of type string, null given, called in /var/www/app/public/autor.php on line 9 and defined in /var/www/app/public/includes/blog-helpers.php:151 Stack trace: #0 /var/www/app/public/autor.php(9): getBlogPostsByAuthor() #1 /var/www/app/public/index.php(408): include('...') #2 {main} thrown in /var/www/app/public/includes/blog-helpers.php on line 151