Fatal error: Uncaught Error: mktime(): Argument #6 ($year) must be of type ?int, string given
in /home/vuser11/6/1/0180816/www.mizumirai.com/cont/wp-includes/class-wp-date-query.php on line 320

コールスタック:

1. mktime()
   wp-includes/class-wp-date-query.php:320
2. WP_Date_Query::validate_date_values()
   wp-includes/class-wp-date-query.php:220
3. WP_Date_Query::sanitize_query()
   wp-includes/class-wp-date-query.php:232
4. WP_Date_Query::sanitize_query()
   wp-includes/class-wp-date-query.php:174
5. WP_Date_Query::__construct()
   wp-includes/class-wp-query.php:2106
6. WP_Query::get_posts()
   wp-includes/class-wp-query.php:3824
7. WP_Query::query()
   wp-includes/class-wp-query.php:3956
8. WP_Query::__construct()
   wp-content/themes/mizumirai_theme/date.php:32
9. include()
   wp-includes/template-loader.php:113
10. require_once()
    wp-blog-header.php:19
11. require()
    /home/vuser11/6/1/0180816/www.mizumirai.com/index.php:17