Unable to connect to secure websocket

Hi! I’m having trouble setting up my WebSocket server in Digital Ocean.

I’m changing my actual domain name for for the question’s sake.

I basically have a NodeJs WebSocket server that I’m trying to connect to a react app I’m hosting at Heroku. I’m getting the following error when attempting to connect:

WebSocket connection to 'wss://' failed: Error during WebSocket handshake: Unexpected response code: 200

Here’s my server entry code:

        const PORT = process.env.PORT || 8080
        const privateKey = fs.readFileSync('/etc/letsencrypt/live/', 'utf-8')
        const certificate = fs.readFileSync('/etc/letsencrypt/live/', 'utf-8')
        const credentials = { key: privateKey, cert: certificate }

        const server = express()
        const httpsServer = https.createServer(credentials, server)

        this.wss = new WebSocket.Server({ server: httpsServer })

I used cert-bot to secure my connection, as for Heroku is obligatory. So here’s my nginx default config file, located at /etc/nginx/sites-available/default

server {

        # SSL configuration
        # listen 443 ssl default_server;
        # listen [::]:443 ssl default_server;
        # Note: You should disable gzip for SSL traffic.
        # See:
        # Read up on ssl_ciphers to ensure a secure configuration.
        # See:
        # Self signed certs generated by the ssl-cert package
        # Don't use them in a production server!
        # include snippets/snakeoil.conf;

        root /var/www/html;

        # Add index.php to the list if you are using PHP
        index index.html index.htm index.nginx-debian.html;


        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                try_files $uri $uri/ =404;

        # pass PHP scripts to FastCGI server
        #location ~ \.php$ {
        # include snippets/fastcgi-php.conf;
        # # With php-fpm (or other unix sockets):
        # fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
        # # With php-cgi (or other tcp sockets):
        # fastcgi_pass;

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #location ~ /\.ht {
        # deny all;

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

I also changed a bit my UFW config. Here’s the output to sudo ufw status

Nginx Full                 ALLOW       Anywhere                  
22/tcp                     ALLOW       Anywhere                  
Nginx Full (v6)            ALLOW       Anywhere (v6)             
22/tcp (v6)                ALLOW       Anywhere (v6)             

Just to be clear, I’m NOT using for real. I just changed it in the current question for privacy concerns, :D

Hope anyone can point me in the right direction. Not really sure where I’m going wrong.

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Maybe you already figure out. But just in case, there is no certificate needed on node.js server. Just configure certificates on nginx. Thought these http and web sockets are same.