Post external links to 404 page

This is my first post in the wordpress support forum.

When I add external links to Facebook and Twitter, It doesn’t redirect to the Facebook and Twitter pages. Instead it redirects to a page not found on my blog.

Example : http://www.vistablog9ja.com.ng/happy-new-month-to-all-vistablog9jas-readers/

The hyperlinked Facebook and Twitter redirects within WordPress and not the external links