Fatal error: Uncaught TypeError: mktime(): Argument #6 ($year) must be of type ?int, string given in /home/kalender/domains/online-kalender.nl/public_html/functions.php:87 Stack trace: #0 /home/kalender/domains/online-kalender.nl/public_html/functions.php(87): mktime() #1 /home/kalender/domains/online-kalender.nl/public_html/index.php(75): setHolidays() #2 {main} thrown in /home/kalender/domains/online-kalender.nl/public_html/functions.php on line 87