start Date could not be converted to date object.Check date and global timezone.

bool(false) object(DateTimeZone)#16983 (2) { ["timezone_type"]=> int(3) ["timezone"]=> string(13) "Europe/Berlin" }
Warning: date_time_set() expects parameter 1 to be DateTime, bool given in /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php on line 2122

Error: Start data of range is not a date object. Please advise administrator

bool(false)
Warning: date_modify() expects parameter 1 to be DateTime, null given in /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php on line 2149

Warning: date_modify() expects parameter 1 to be DateTime, null given in /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php on line 2152

Fatal error: Uncaught Error: __clone method called on non-object in /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php:1450 Stack trace: #0 /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php(1696): amr_process_icalevents(Array, false, NULL, '30') #1 /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php(2218): amr_process_icalspec(Array, false, NULL, '30') #2 /www/htdocs/v034011/projects/www2.tbuddy.de/wp-includes/shortcodes.php(433): amr_do_ical_shortcode(Array, '', 'ical') #3 [internal function]: do_shortcode_tag(Array) #4 /www/htdocs/v034011/projects/www2.tbuddy.de/wp-includes/shortcodes.php(273): preg_replace_callback('/\\[(\\[?)(ical)(...', 'do_shortcode_ta...', '[ical https://a...') #5 /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/codeblock.php(31 in /www/htdocs/v034011/projects/www2.tbuddy.de/wp-content/plugins/amr-ical-events-list/includes/amr-ical-events-list-main.php on line 1450