Critical Error on form submission

I always have the website crash and report a critical error when the first section of the form is submitted

here are the debugging logs:



[29-Jun-2023 17:22:38 UTC] PHP Fatal error: Uncaught TypeError: mktime(): Argument #5 ($day) must be of type ?int, string given in /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable-pro/classes/helpers/FrmProAppHelper.php:304
Stack trace:

0 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable-pro/classes/helpers/FrmProAppHelper.php(304): mktime()

1 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable-pro/classes/helpers/FrmProAppHelper.php(282): FrmProAppHelper::convert_date_fallback()

2 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable-pro/classes/models/fields/FrmProFieldDate.php(195): FrmProAppHelper::convert_date()

3 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable/classes/models/FrmEntryValidate.php(192): FrmProFieldDate->validate()

4 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable/classes/models/FrmEntryValidate.php(134): FrmEntryValidate::validate_field_types()

5 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable/classes/models/FrmEntryValidate.php(36): FrmEntryValidate::validate_field()

6 /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable/classes/controllers/FrmEntriesController.php(537): FrmEntryValidate::validate()

7 /home/u170293477/domains/edu-seeker.com/public_html/wp-includes/class-wp-hook.php(306): FrmEntriesController::process_entry()

8 /home/u170293477/domains/edu-seeker.com/public_html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters()

9 /home/u170293477/domains/edu-seeker.com/public_html/wp-includes/plugin.php(517): WP_Hook->do_action()

10 /home/u170293477/domains/edu-seeker.com/public_html/wp-settings.php(645): do_action()

11 /home/u170293477/domains/edu-seeker.com/public_html/wp-config.php(109): require_once('/home/u17029347…')

12 /home/u170293477/domains/edu-seeker.com/public_html/wp-load.php(50): require_once('/home/u17029347…')

13 /home/u170293477/domains/edu-seeker.com/public_html/wp-admin/admin-ajax.php(22): require_once('/home/u17029347…')

14 {main}

thrown in /home/u170293477/domains/edu-seeker.com/public_html/wp-content/plugins/formidable-pro/classes/helpers/FrmProAppHelper.php on line 304