Fatal error: Uncaught TypeError: Return value of Cover::getConfiguration() must be an instance of mixed, string returned in /var/www/vhosts/adriverhoeven.nl/httpdocs/admin/classes/Cover.php:88 Stack trace: #0 /var/www/vhosts/adriverhoeven.nl/httpdocs/index.php(20): Cover->getConfiguration() #1 /var/www/vhosts/adriverhoeven.nl/httpdocs/redirect.php(53): include('/var/www/vhosts...') #2 {main} thrown in /var/www/vhosts/adriverhoeven.nl/httpdocs/admin/classes/Cover.php on line 88