[Plugin: WP User Frontend] WordPress database when posting new post via frontend

Hello,
I’ve noticed that I get MYSQL syntax error when posting the new post via frontend (add post).
I’m using DirectoryPress theme and WP Deal plugin.
Error message:
WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘AND post_type IN (‘post’) and post_status = ‘publish” at line 1 for query SELECT COUNT(*) FROM wp_posts WHERE post_author = AND post_type IN (‘post’) and post_status = ‘publish’ made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/plugins/wp-deals/deals-template/single-deal.php’), do_action(‘deals_sidebar’), call_user_func_array, deals_output_sidebar, get_sidebar, locate_template, load_template, require_once(‘/themes/directorypress/sidebar.php’), include(‘/themes/directorypress/template_directorypress/_sidebar.php’), PremiumPressTheme_Design->GetObject

Thank You!
Dogen

https://www.ads-software.com/extend/plugins/wp-user-frontend/