Permalinks updated but receive error 404

Hi,

I have update my permalinks to use Post name structure. It is updated.
https://docnantees.com/wp-content/uploads/2015/07/1-permalink-is-updated.png

But once i clicked the post, it show error 404 (not found).
https://docnantees.com/wp-content/uploads/2015/07/3-not-found.png

What should i do?

Thanks