How can DNS propagation cause delivery errors?

DNS propagation can cause temporary delivery problems:

What propagation means:

DNS changes take time to spread globally. Different resolvers may have different cached values. Old records may persist for their TTL duration.

Email impact scenarios:

New domain: MX records not yet visible everywhere. Changed MX: Some servers route to old destination. Moved domain: Old nameservers still being queried.

Typical propagation times:

Minutes to hours for low-TTL records. Up to 48 hours for full global propagation. Depends on TTL values set.

Symptoms:

Intermittent delivery success/failure. Different results from different locations. "Host not found" for newly configured domain.

Resolution:

Wait for propagation to complete. Plan DNS changes in advance. Use low TTL before major changes.

Propagation is the tide of DNS updates. Wait for it to reach all shores.