reference

Fatal error: Uncaught Error: Object of class stdClass could not be converted to string
in /home/vanequip/public_html/wp-includes/class-wp-tax-query.php on line 559

Call stack:

1. array_unique()
   wp-includes/class-wp-tax-query.php:559
2. WP_Tax_Query::clean_query()
   wp-includes/class-wp-tax-query.php:394
3. WP_Tax_Query::get_sql_for_clause()
   wp-includes/class-wp-tax-query.php:324
4. WP_Tax_Query::get_sql_for_query()
   wp-includes/class-wp-tax-query.php:274
5. WP_Tax_Query::get_sql_clauses()
   wp-includes/class-wp-tax-query.php:250
6. WP_Tax_Query::get_sql()
   wp-includes/class-wp-query.php:2133
7. WP_Query::get_posts()
   wp-includes/class-wp-query.php:3448
8. WP_Query::query()
   wp-includes/class-wp-query.php:3559
9. WP_Query::__construct()
   wp-content/themes/van/archive.php:22
10. include()
    wp-includes/template-loader.php:106
11. require_once()
    wp-blog-header.php:19
12. require()
    index.php:17