You have a couple of different warning/error messages there.
Warning: Cannot modify header information - headers already sent by (output started at /home//public_html/wp-includes/wp-db.php:1520) in /home//public_html/wp-content/plugins/wordpress-seo/admin/class-admin-init.php on line 84That may be related to the wordpress-seo plugin. Disable it and see if the error changes or goes away. Make sure you have the latest version.