Sitemap Question

Hey Joost,

My sitemap is displaying correctly on our dev environment but not on the production site. Can you compare these two and tell me why. The source code is exactly the same. I did get into the PHP file handling the .xsl and corrected and error that was rendering in the stylesheet but still no fix.

Working: http://www.usalaw.bssdev.com/sitemap_index.xml
Not Working: http://www.usalaw.com/sitemap_index.xml

Thank you in advance for any clarity.

https://wordpress.org/plugins/wordpress-seo/