Connection errors in Asia Pacific region on July 9, 2023

Cloudflare experienced a DNS resolution issue due to expired signatures in .com and .net zones managed by Verisign, which caused connection errors for some customers. The error rate decreased significantly after rerouting DNS traffic via IPv6, but the underlying problem was not resolved until July 10th when Verisign confirmed they were serving stale data and had fixed the issue. Cloudflare is working on improving incident communication channels with other providers to address similar issues more efficiently in the future. The impact of this DNS failure highlights the importance of robust DNS systems for maintaining a reliable Internet experience. Question: How does CNAME flattening affect external DNS resolution?