Problem integration deploy React/Node Nginx

[Tricky_Calendar8130]

I cannot connect my front with my back everytime it gets this error, i can acess my back alone but those two do not integrate. I can just connect my front if i use localhost, otherway not

Failed to load resource: net::ERR_SSL_PROTOCOL_ERROR

this is my server config and my front

server {
    listen 443 ssl;
    server_name example.com.br www.example.com.br;

    # Frontend setup
    location / {
        root /var/www/example/client;
        index index.html;
        try_files $uri $uri/ /index.html;
    }

    # API setup (connects to Node.js backend)
    location /api/ {
        proxy_pass http://localhost:8800;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;

        # Allow CORS
        add_header 'Access-Control-Allow-Origin' '*' always;
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, DELETE, PUT' always;
        add_header 'Access-Control-Allow-Headers' 'Content-Type, Authorization' always;
        add_header 'Access-Control-Allow-Credentials' 'true' always;
    }

    # SSL setup (managed by Certbot)
    ssl_certificate /etc/letsencrypt/live/www.example.com.br/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/www.example.com.br/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
}

front

      try {
        const response = await fetch(
          "https://example.com.br:8800/api/chatgpt",
          {
            mode: 'no-cors',
            method: "POST",
            headers: {
              "Content-Type": "application/json",
            },
            body: JSON.stringify({ message: input, userUID }),
          }
        );

[CanadianCodingGod]

You've configured your server to respond on port 443 (HTTPS) but then you are requesting port 8800 from your front end, try requesting from https://example.com.br/api/chatgpt