Nginx + Gunicorn + Pyramid output static on port 8000 instead of 80, how to fix?

Question

Python

Good day to all!
Installed nginx, gunicorn, pyramid framework on vds.
nginx settings file (/etc/nginx/sites-available/default):

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;
    access_log  /var/log/nginx/myproject.log;

    location /static/ {
        root /root/myproject/appname/appname;
        expires 30d;
    }

    location / {
        proxy_pass http://127.0.0.1:8000;
        proxy_set_header Host $server_name;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
  }

I launch Gunicorn with the command:
gunicorn --paste development.ini -b :8000
As a result, at http://[site_name].ru the site loads without static, but at http://[site_name].ru:8000 the site loads normally . In this case, links in the source code of the page in the first case look like href="http://127.0.0.1:8000/static/file.png", and in the second case href="http://[site_name].ru:8000/static/file.png". Before that, there was a Bottle Framework with the same nginx settings and everything worked fine. How to fix this situation?
Kick, please, in the right direction.