title: HTTP 404 with Post name permalink
body: <p>Okay so I've just create the first page on this site. It works when I use the default permalink settings.</p>
  
  <p>If I change the permalink settings to use Post name, then I get an HTTP 404.</p>
  
  <p>I'm not sure what's gone wrong or if I've broken anything. Can anyone help me fix?</p>
  
  <p>The site is hosted on apache.</p>
  
  <p><img src="https://i.stack.imgur.com/snTKm.png" alt="Page exists, link is broken"></p>