4.7.1 — Temporary deferral (“try again later”)

What 4.7.1 means

4.7.1 is a temporary policy-related status. The receiver is not accepting the message right now, but is indicating that delivery may succeed later. Many systems do this intentionally to slow down unknown senders or to protect their infrastructure under load.

Common causes

Rate limiting / throttling

You are sending too fast for the receiver’s limits, or the receiver is applying a conservative policy to your sender identity. The exact thresholds are provider-specific.

Greylisting

Greylisting temporarily rejects first-time attempts and expects legitimate MTAs to retry. If your sending system retries properly, delivery usually succeeds on a later attempt.

Temporary policy deferral

Some providers defer messages when reputation signals are incomplete or when authentication and identity signals are inconsistent. This can happen with new IPs/domains or sudden volume spikes.

What it looks like

Action: delayed
Status: 4.7.1
Diagnostic-Code: smtp; 451 4.7.1 Try again later

Action: delayed
Status: 4.7.1
Diagnostic-Code: smtp; 451 4.7.1 Temporary rate limit exceeded

Next steps

If you are the sender

• Ensure your system retries with exponential backoff (not rapid-fire retries).
• Reduce bursty traffic; smooth sending rate, especially to a single provider/domain.
• Keep authentication consistent (SPF/DKIM/DMARC aligned with the domain in From:).
• If you are on new infrastructure, ramp volume gradually and keep lists clean.
• If deferrals persist for many hours/days, treat it as a trust/reputation issue rather than a transient glitch.

If you administer the receiving system

• Confirm whether greylisting or rate limit rules are active and whether they behave as intended.
• Check whether legitimate senders are stuck due to overly strict thresholds.
• Consider returning helpful diagnostic wording (it reduces support load).

Related codes

Temporary policy deferrals often cluster around 4.7.x. Permanent policy rejections are frequently 5.7.1 (see 5.7.1). Browse the full list: /bouncecodes/.