IPv6 Website Check
Check if a website supports IPv6 access, promoting IPv6 adoption
Possible reasons the website does not support IPv6:
1. The server has IPv6 disabled, see Three ways to enable IPv6 on your website
2. The server has IPv6 but the firewall does not allow port 443 (HTTPS) from IPv6 (::/0)
3. The server has IPv6 but no SSL certificate, see Enable IPv6 SSL in Nginx