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When mail arrives at JetEmail and your destination mail server is unreachable, we don’t reject or drop the message. We hold it in our queue and retry delivery automatically until either the destination accepts it or the retention window expires.

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How long we hold mail

JetEmail holds queued mail for up to 5 days from the time it first arrived. During that window we retry delivery to your destination on a backoff schedule, attempting more frequently shortly after the failure and gradually less often the longer the outage continues. If your destination comes back online within the 5 day window, every queued message for your domain delivers automatically. There is nothing to do on your side. If the destination is still offline after 5 days, the queued message is returned to the original sender as a non-delivery report (NDR). The sender can choose whether to resend.

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What counts as “offline”

The destination is treated as offline when JetEmail can’t successfully deliver. Common causes include:
  • Server is powered off, restarting, or unreachable on the network
  • The destination port (e.g. 25 or 587) is blocked by a firewall
  • Destination accepts the connection but returns a temporary failure (4xx SMTP response)
  • TLS handshake fails persistently
  • DNS resolution for the destination hostname fails
Permanent failures (5xx SMTP responses) are not retried. The message is returned to the sender immediately.

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Checking queued mail

Use the dashboard’s Logs view under the affected inbound domain to see what’s currently held and what has been delivered or returned. Each queued message shows the next retry time and the reason for the most recent failure, which is the fastest way to diagnose why delivery isn’t happening.

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When delivery resumes

Once your destination accepts mail again, the queue drains automatically. You don’t need to trigger a manual retry. If the outage was long, expect a brief burst of delivery as queued mail flushes through.

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What this is not

  • It is not a permanent mailbox. JetEmail is a filter and relay, not a mail store. The 5 day window is a delivery buffer, not long-term retention.
  • It is not a backup MX in the traditional sense. All inbound mail for your domain flows through JetEmail; there’s no separate “primary then secondary” arrangement to configure.
  • It does not extend mail loss tolerance beyond 5 days. If you anticipate longer outages, plan a destination that has its own redundancy (e.g. a mailbox provider with HA, or your own clustered server) rather than relying on the queue window.

Set destination

Configure where filtered mail is delivered after it leaves our queue.

Email logs

Check delivery status, retry counts, and failure reasons for any inbound message.