The service is currently having an issue on IP4 networks, with Cloudflare saying:
Investigating – Cloudflare is currently seeing query timeouts for our IPv4 addresses for our public DNS resolver (18.104.22.168 and 22.214.171.124). IPv6 addresses are currently not affected (2606:4700:4700::1111 and 2606:4700:4700::1001). We are investigating further and will provide updates as they become available.
Bron: https://mspoweruser.com/cloudflares-1-1 ... down-hard/