logo
421 4.7.0

Try again later (rate limited or deferred)

The server is asking you to slow down or come back later. It is a temporary answer, and a well-behaved sender retries after a pause instead of giving up or hammering the server.

TypeTemporary failure (soft bounce)
Retry?Yes, after a pause
The addressProbably fine, try later

Common causes

  • You sent too many messages or connections in a short time.
  • The provider is throttling new or low-reputation senders.
  • The receiving server is overloaded for a moment.
  • A spike of complaints made the provider cautious about your domain.

How to fix it

  1. Let your mail system retry on its own schedule; do not resend by hand.
  2. Lower the sending speed and send in smaller batches.
  3. Warm up new domains and IPs gradually.
  4. If it repeats for days, look at your reputation and complaint rate.

Frequently asked questions

How long should I wait?

Mail servers normally retry for several hours up to a few days. If the message is still deferred after that, treat the cause as a reputation problem.

Does verification have this problem too?

Large providers limit how fast anyone can check mailboxes. Mailcut paces its checks per provider and reports addresses it could not confirm as Unknown instead of guessing.

Start with free credits

Create an account, check your first addresses and see the report. No card needed.

Create free account