Nginx Reverse Proxy with HTTPS not working

I had successfully got the cert of my SSL and now I was trying to implement it into my AWS server with NGINX reserve proxy setup, here is the config file:

server {
listen 80;
server_name example.com;
return 301 https://www.example.com$request_uri;
}

server {
listen 443 ssl;
ssl_certificate /etc/nginx/ssl/cert_chain.crt;
ssl_certificate_key /etc/nginx/ssl/website.key;
server_name ~^(?<subdomain>.+)\.example\.com$;

location / {
proxy_pass http://www.example.com:8888;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $subdomain.example.com;
proxy_cache_bypass $http_upgrade;
}
}

If I change the setting to listen to port 80 then it's working fine. I had enabled port 443 in AWS security group and here is the result of netstat -tulpn | grep 443:

(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN -

So it means it's listening to port 443 already right? I also ensured that the nginx was run as root using ps aux|grep nginx|grep -v grep:

root 11567 0.0 0.3 177080 3060 ? Ss 09:36 0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
www-data 11568 0.0 0.7 177344 7568 ? S 09:36 0:00 nginx: worker process

I had checked the Nginx error log and it got nothing inside, but when I access my url with https it just showing that it took too long to respond. Anyone able to help? Thank you.