451 4.7.1 — Too many messages from your address (Yandex)
TemporaryReputation
Retrying later can work — at a lower rate, not the same one.
The reply
451 4.7.1 Too many messages from your address. Try again later.A rate limit, not a block. Yandex will accept this mail later; how much later depends on whether you slow down or keep pushing.
What it means
A temporary deferral applied per sending address or IP. Yandex sets the ceiling from how familiar it is with the sender, so a new domain hits it at volumes an established one never notices. Retrying is correct, retrying at the same concurrency is not.
Why it happens
- Too many messages or connections per unit time from one address.
- A new domain or IP sending at a volume its history does not support.
- A campaign dispatched as a burst rather than spread out.
What to do
- Reduce concurrency and spread the send across a longer window.
- Retry with exponential backoff.
- Grow volume gradually while the sender is new to Yandex.
- Keep an even hourly rate instead of large bursts.
Questions
How long until it clears?
Usually minutes to a couple of hours, provided the rate actually comes down. If deferrals continue at a reduced rate, the limit is reputation-driven rather than throughput-driven.