Fatal error: Uncaught TypeError: array_keys(): Argument #1 ($array) must be of type array, null given in /home/wwwthews/public_html/online/calendar.php:56 Stack trace: #0 /home/wwwthews/public_html/online/calendar.php(56): array_keys(NULL) #1 {main} thrown in /home/wwwthews/public_html/online/calendar.php on line 56