Why is redirect not working in WordPress?

Question

htaccess

There is a site on WP
CNC was configured as Day and the name sitename/2016/09/27/sample-post
there is a desire to reconfigure to Post name sitename/sample-post
heard that WP automatically redirects, but does not work. Old links Page not found.
Moreover, if you return it as it was, and go to other CNC options, it redirects correctly.
What to do?

Answer 1

solved
RedirectMatch 301 /([0-9]+)/([0-9]+)/([0-9]+)/(.*)$ www.domain.com/$4