I need the posts to show the author for each posts.

I went to Post & Pages
Edit post page info items
BYLINE: Multi Post Pages
BYLINE: Single Post Pages
and set the value to default:

By %author%, on %date('F jS, Y')%

Initially it showed the author and the date, but as I tried to modify the value to other defaults, it stopped working and is not working anymore. I tried to reset this page in Atahualpa settings to default settings, still authors don't show.

My site with posts is here:
http://www.humancolony.org/posts/

Please help.

what exactly do you have in ALL the 'BYLINE…' options