将 WWW 重定向到非 WWW 不起作用（CERTBOT、NGINX、GUNICORN、FLASK）

我最近遇到了 Flask-WTF 的问题，我需要在应用程序的配置中设置 SERVER_NAME 以便 CSRF 令牌可以工作。这很好用，但现在如果不转到我放入 SERVER_NAME 环境变量中的正确域，我就看不到我的 python 加载的工作。在我看来，我对此的解决方案是从www.websitename.com http://www.websitename.com到 websitename.com。然而创建一个/etc/nginx/conf.d/redirect.conf包含这些内容：

server {
    server_name www.websitename.com;
    return 301 $scheme://websitename.com$request_uri;
}

并拥有/etc/nginx/sites-enabled/webapp包含：

server {
        server_name websitename.com www.websitename.com;

        location /static {
                alias /home/sai/webapp/website/static;
        }

        location / {
                proxy_pass http://localhost:8000;
                include /etc/nginx/proxy_params;
                proxy_redirect off;
        }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/www.websitename.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/www.websitename.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}


server {
    if ($host = websitename.com) {
        return 301 https://$host$request_uri;
    } #managed by Certbot

        listen 80;
        server_name websitename.com
    return 404;
}

server {
    if ($host = www.websitename.com) {
        return 301 https://websitename.com$request_uri;
    }
        listen 80;
        server_name www.websitename.com
    return 404;
}

不起作用。我仍然没有被重定向，并且仍然看不到任何 Gunicorn 内容。