I receive this message when I try to do anything with the Plugin. Please help, thank you!
Warning: Cannot modify header information - headers already sent by (output started at /home/myo/public_html/wp-admin/includes/template.php:1642) in /home/myo/public_html/wp-includes/pluggable.php on line 876
Additionally, when I click the XML sitemap button, I'm brought to a 404 page.
Any help would be greatly appreciated. Thank you.