don't run nginx but OS 7 I do. Googling found a person having similar issue ... wasn't redirecting for https.
the default site configuration from /etc/nginx/sites-enabled/ still present deleting that symbolic link fixes the problem
i can get to http://site/ but only if include index.php which wouldn't be doing site redirect to https. otherwse https begets FF error unable 2 connect.
'spirit of sharing' Ken