DNS resolution failed (NXDOMAIN, no answer)

What it usually means

The hostname never resolved to an address, so nothing was ever contacted. Check the record still exists at your DNS provider, and that the zone has not expired or been moved.

What to check first

• The A/AAAA (or CNAME) record still exists at your DNS provider and points where you think it does.
• The domain has not expired: an expired domain is the most common cause of a name that suddenly stops resolving.
• The nameservers at the registrar match the ones your DNS provider expects (a migration that never finished).
• Propagation: a record changed in the last 24 hours may still be cached with its old TTL by some resolvers.

How ErrorDetector reports it

This is a reachability failure. The check is repeated immediately to rule out a blip; once confirmed, an incident opens with this cause on it, every channel on the monitor is alerted, and the outage counts against uptime until the next successful check closes the incident.

Caught by: httpkeywordapidnspingport monitors. Read about the dns monitoring feature.