: Uncaught TypeError: array_unique(): Argument #1 ($array) must be of type array, null given in /var/www/demo.graphpaperpress.com/public_html/wp-includes/post-template.php:859
Stack trace:
#0 /var/www/demo.graphpaperpress.com/public_html/wp-includes/post-template.php(859): array_unique()
#1 /var/www/demo.graphpaperpress.com/public_html/wp-includes/post-template.php(620): get_body_class()
#2 /var/www/demo.graphpaperpress.com/public_html/wp-content/themes/qua/header.php(23): body_class()
#3 /var/www/demo.graphpaperpress.com/public_html/wp-includes/template.php(790): require_once('...')
#4 /var/www/demo.graphpaperpress.com/public_html/wp-includes/template.php(725): load_template()
#5 /var/www/demo.graphpaperpress.com/public_html/wp-includes/general-template.php(48): locate_template()
#6 /var/www/demo.graphpaperpress.com/public_html/wp-content/themes/qua/404.php(8): get_header()
#7 /var/www/demo.graphpaperpress.com/public_html/wp-includes/template-loader.php(106): include('...')
#8 /var/www/demo.graphpaperpress.com/public_html/wp-blog-header.php(19): require_once('...')
#9 /var/www/demo.graphpaperpress.com/public_html/index.php(17): require('...')
#10 {main}
thrown in /var/www/demo.graphpaperpress.com/public_html/wp-includes/post-template.php on line 859