For many years, I have used the Cloudflare DNS (1.1.1.1) without any substantial issues. However, today a fairly common survey platform my team uses frequently (Qualtrics) ran into an issue. In short, when using the Cloudflare DNS, it refused to resolve subdomains (e.g., x.qualtrics dot com). Changing my DNS back to auto for the standard ISP caused these subdomains to work fine again.
The error on Chrome was:
# This site can’t be reached
Check if there is a typo in usc.qualtrics.com.
* If spelling is correct, [try running Windows Network Diagnostics](javascript:diagnoseErrors()).
DNS_PROBE_FINISHED_NXDOMAIN
Is there any guidance on why this behavior has started with the Cloudflare DNS? I would assume it has something to do with Cloudflare vs. Qualtrics having different opinions on protocols for subdomains, but we can’t resume using Cloudflare’s DNS until we sort this out. The subdomains appear to work fine through other DNS resolvers.