Nginx Proxy : Error Code Respon 400 | The plain HTTP request was sent to HTTPS port

Problem :

URL is http://domain.com:443/….

protocol http is difference than port

Solution :

edit nginx vhost like this :
upstream domain.com {
        server 192.168.1.15:8401;
}

server {
        if ($host = domain.com) { return 301 https://$host$request_uri; }
        if ($host = www.domain.com) { return 301 https://$host$request_uri; }

        listen 80;
        server_name domain.com *.domain.com;
        return 404;
}

server {
        listen 443 ssl http2;
        server_name domain.com www.domain.com;

        ssl_certificate /etc/letsencrypt/live/domain.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/domain.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

        add_header Content-Security-Policy "upgrade-insecure-requests";
        error_page 497 301 =307 https://$host:$server_port$request_uri;
        if ($scheme = http) { return 301 https://$host$request_uri; }

        location / {
                proxy_pass                      http://domain.com;
                proxy_redirect                  http:// https://;
                # proxy_redirect                http:// $scheme://;
                proxy_set_header                X-Scheme $scheme;
                # proxy_ssl_protocols           TLSv1 TLSv1.1 TLSv1.2;
                proxy_redirect                  http://192.168.1.15:8401 https://domain.com;
                # proxy_ssl_server_name         on;
                proxy_set_header                Host $host;
                # proxy_set_header              Host $host:$server_port;
                proxy_set_header                X-Real-IP $remote_addr;
                proxy_set_header                X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header                X-Forwarded-Proto $scheme;
                proxy_set_header                X-FORWARDED-PROTO https;
                proxy_set_header                X-Forwarded-Port 443;
                proxy_set_header                X-Forwarded-Proto $scheme;
                proxy_redirect                  off;
                proxy_http_version              1.1;
                proxy_set_header                Upgrade $http_upgrade;
                proxy_set_header                Connection 'upgrade';
                proxy_cache_bypass              $http_upgrade;
                proxy_headers_hash_max_size     1024;
                proxy_headers_hash_bucket_size  1024;
        }
}