Running a flask app with nginx and gunicorn

I'm new at this and have only been using nginx to serve static files. I have now installed flask and gunicorn. If I run gunicorn -b 127.0.0.2:8000 hello:app and then wget it from the server it works well. If I try to access it from a browser, however, it returns a 404 error (I am running this on a server that hosts a wordpress site which is locatet at root).

The flask app:

from flask import Flask
from werkzeug.contrib.fixers import ProxyFix
app = Flask(__name__)

@app.route('/')
def hello():
    return "Hello world!"

app.wsgi_app = ProxyFix(app.wsgi_app)

if __name__ == '__main__':
    app.run()

And the relevant part of my nginx configuration:

location /flask {
                 proxy_set_header       Host            $http_host;
                 proxy_set_header       X-Real-IP       $remote_addr;
                 proxy_set_header       X-Forwarded-For $proxy_add_x_forwarded_\
for;
                 proxy_pass             http://127.0.0.2:8000;
                 proxy_redirect         off;
    }

I hope this is all the relevant info. If not, do tell. Thanks!

This is how I serve my flask apps in Nginx:

Run gunicorn daemonized using a socket:

  sudo gunicorn app:app --bind unix:/tmp/gunicorn_flask.sock -w 4 -D

Related nginx config:

    upstream flask_server {
        # swap the commented lines below to switch between socket and port
        server unix:/tmp/gunicorn_flask.sock fail_timeout=0;
        #server 127.0.0.1:5000 fail_timeout=0;
    }
    server {
        listen 80;
        server_name www.example.com;
        return 301 $scheme://example.com$request_uri;
    }

    server {
        listen 80;
        client_max_body_size 4G;
        server_name example.com;

        keepalive_timeout 5;

        # path for static files
        location  /static {
            alias /path/to/static;
            autoindex on;
            expires max;
        }

        location / {
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_redirect off;

            if (!-f $request_filename) {
                proxy_pass http://flask_server;
                break;
            }
        }
    }

}