I had the permalink structure set to date/postname/, but since I only had two posts and this was a new blog, I decided to change it to where it just had the /postname/.
Well, when I did, nothing worked. All permalink go to "page not found", even if I publish a new post!
If I try to go back, it still goes to page not found.
It works if I go back to the default, but no matter what other option I choose, nothing else works.