samgul on "[Plugin: WordPress SEO by Yoast] I don't see anything in my category pages!"

Hello.
I use the latest version of Wopdpress.
Before it was ok. But Yesterday I changed some options in SEO Yoast. I don't remember what they were. Now I click my menu with category and see that this page was not founded. What shoul I do to correct my mistake?
Thank you.

http://wordpress.org/extend/plugins/wordpress-seo/