Web2py application is not launched with NGiNX

Question

I have created a website with Web2py framework. To launch it on production, uWSGI app and NGiNX server were used as it was described here.

Both NGiNX and uWSGI are running, Web2py also does, but the website pages can not be opened. Browser returns error "502 Bad gateway". Please tell how can I fix this problem?

File /etc/nginx/sites-available/web2py :

server {
        listen          80;
        server_name     $hostname;
        root html;
        index index.html index.htm;
        location ~* /(\w+)/static/ {
            root /home/www-data/web2py/applications/;
            #remove next comment on production
            #expires max;
        }
        location / {
            uwsgi_pass      unix:///tmp/web2py.socket;
            include         uwsgi_params;
            uwsgi_param     UWSGI_SCHEME $scheme;
            uwsgi_param     SERVER_SOFTWARE    nginx/$nginx_version;
        }
}
server {
        listen 443 default_server ssl;
        server_name     $hostname;
        ssl_certificate         /etc/nginx/ssl/web2py.crt;
        ssl_certificate_key     /etc/nginx/ssl/web2py.key;
        ssl_prefer_server_ciphers on;
        ssl_session_cache shared:SSL:10m;
        ssl_session_timeout 10m;
        ssl_ciphers ECDHE-RSA-AES256-SHA:DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        keepalive_timeout    70;
        location / {
            uwsgi_pass      unix:///tmp/web2py.socket;
            include         uwsgi_params;
            uwsgi_param     UWSGI_SCHEME $scheme;
            uwsgi_param     SERVER_SOFTWARE    nginx/$nginx_version;
        }

}

File /etc/init/uwsgi-emperor.conf :

description "uWSGI Emperor"
start on runlevel [2345]
stop on runlevel [06]
respawn
exec uwsgi --master --die-on-term --emperor /etc/uwsgi --logto /var/log/uwsgi/uwsgi.log

File # /etc/systemd/system/emperor.uwsgi.service:

[Unit]
Description = uWSGI Emperor
After = syslog.target

[Service]
ExecStart = /usr/bin/uwsgi --ini /etc/uwsgi/web2py.ini
RuntimeDirectory = uwsgi
KillSignal = SIGQUIT
Type = notify
StandardError = syslog
NotifyAccess = all

[Install]
WantedBy = multi-user.target

File /etc/uwsgi/web2py.ini

[uwsgi]

socket = /tmp/web2py.socket
pythonpath = /home/www-data/web2py/
mount = /=wsgihandler:application
processes = 4
master = true
harakiri = 60
reload-mercy = 8
cpu-affinity = 1
stats = /tmp/stats.socket
max-requests = 2000
limit-as = 512
reload-on-as = 256
reload-on-rss = 192
uid = www-data
gid = www-data
touch-reload = /home/www-data/web2py/routes.py
cron = 0 0 -1 -1 -1 python /home/www-data/web2py/web2py.py -Q -S welcome -M -R scripts/sessions2trash.py -A -o
no-orphans = true
vacuum = true
logto = /var/log/uwsgi/web2py.log