Fatal error: Call to undefined method WP_Query::is_main_query() in /home/xxxxx/public_html/xxxxx/wp-content/plugins/wordpress-seo/frontend/class-frontend.php on line 431 This is the error I get when I install Wordpress SEO by Yoast. I love yoast! But, it's not working with this website. It's a simple one page sales page with a flexsqueeze theme. The error is what shows instead of the website when I active the plugin. When I deactivate the plugin, it goes away and the site comes back. If anyone can help me, I would greatly appreciate it.