Fatal error: Uncaught TypeError: usort(): Argument #1 ($array) must be of type array, null given in /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/class_cal_front.php:439 Stack trace: #0 /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/class_cal_front.php(439): usort(NULL, 'class_cal_front...') #1 /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/class_cal_front.php(83): class_cal_front->get_kalender_daten_eines_kalender(Array) #2 /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/pkalenderplugin_class.php(44): class_cal_front->get_kalender_front() #3 /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/pkalenderplugin_class.php(22): pkalenderplugin_class->pkalender() #4 /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/pkalenderplugin_class.php(684): pkalenderplugin_class->__construct() #5 /www/htdocs/w0115f88/Marlow_2021-2024/lib/classes/pluginintegrator_class.php(82): require_once('/www/htdocs/w01...') #6 /www/htdocs/w0115f88/Marlow_2021-2024/lib/classes/pluginintegrator_class.php(41): pluginintegrator_class->make_classes_integration() #7 /www/htdocs/w0115f88/Marlow_2021-2024/lib/classes/pluginintegrator_class.php(243): pluginintegrator_class->__construct() #8 /www/htdocs/w0115f88/Marlow_2021-2024/lib/classes.php(213): require_once('/www/htdocs/w01...') #9 /www/htdocs/w0115f88/Marlow_2021-2024/lib/includes.inc.php(81): require_once('/www/htdocs/w01...') #10 /www/htdocs/w0115f88/Marlow_2021-2024/all_inc_front.php(23): require_once('/www/htdocs/w01...') #11 /www/htdocs/w0115f88/Marlow_2021-2024/plugin.php(25): require_once('/www/htdocs/w01...') #12 {main} thrown in /www/htdocs/w0115f88/Marlow_2021-2024/plugins/pkalender/lib/class_cal_front.php on line 439