I'm very curious as to why you want to redirect to http while https is better and have better browser support?
And your site runs good in https.
Anyway, if you want http to work you have to check 3 things.
1.) Automatic redirection from within Directadmin had to be disabled
2.) No .htaccess or virtualhost or nginx.conf redirection from http to https must be present
3.) There must not be https main site paths in your website.
Still..... I wouldn't do it if I were you.