Let's Encrypt domain control validation failed for about two hours after a DNS resolver change

Sources: primary, HN item
Summary: The Let's Encrypt status page records a resolved incident of elevated domain control validation failures. The 01:40 UTC update reports elevated failures over the preceding hour and the resolved update carries a 02:39 UTC timestamp, which places the window at roughly two hours. The page scopes the fault to a change to the DNS resolver used in secondary validation.
Why it matters: Certificate issuance and renewal stopped for subscribers during the window, which is the failure automated renewal pipelines carry no fallback for.