Q:

502 error after adding application to a Django project running on nginx and gunicorn

I am trying to add an application to an existing Django project, but once I have done it I get a 502 error. The server is running Ubuntu.  I don't think it has to do with the applications code because I got it running on the django development server.  It goes away when I take out the app's name from settings.py and restart gunicorn.  
Here's a part of the log
2011/07/15 01:24:45 [error] 16136#0: *75593 connect() failed (111: Connection refused)   while connecting to upstream, client: 24.17.8.152, server: staging.site.org, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8020/", host: "staging.site.org"

Here's the nginx config file. 
Nginx Config File
I'm not sure what other information is needed.  Not sure where the gunicorn logs are located.  My server admin skills are kind of lacking. 

A:

Nginx isn't able to connect to your backend (gunicorn) or gunicorn is refusing the connection.  You provided no details about the configuration so that's all the help you'll get.  You are correct that the application code has nothing to do with it.  It's a configuration error on your part.