Enhanced Status Code 5.2.122: Recipient Hourly Receive Limit Exceeded
Enhanced Status Code 5.2.122 means “Recipient Hourly Receive Limit Exceeded.” The recipient is receiving more mail per hour than Microsoft allows, counting every source. The limit belongs to them, not to you, so slowing your own sending has limited effect.
550 5.2.122 Recipient's per hour message receive limit exceededWhat does 5.2.122 mean?
Microsoft returns 5.2.122 when a recipient's per hour message receive limit has been exceeded across all senders. Unlike 5.2.121, which counts only your traffic to that address, this one counts everything arriving at the mailbox. You are one contributor among many and possibly a small one.
That changes what you can usefully do. Reducing your own rate helps only in proportion to your share of the traffic, and if the mailbox is being flooded from elsewhere your restraint will not clear the condition. It is worth retrying, because the limit is hourly and self-clearing, but it is not worth restructuring your sending on the assumption that you caused it.
Shared and role addresses are the usual subjects. A support@ or alerts@ mailbox subscribed to many systems accumulates traffic from every one of them, and no individual sender is at fault. If a shared address consistently returns this code, the recipient organisation needs to look at what is writing to it, and the useful thing you can do is tell them.
How 5.2.122 plays out
5.2.122 replyWhere 5.2.122 sits: soft vs hard bounce
| Soft bounce (4xx) | Hard bounce (5xx) | |
|---|---|---|
| Nature | Temporary | Permanent |
| SMTP class | 4xx | 5xx |
| What to do | Let it retry | Suppress the address |
| Recoverable? | Often | No |
| 5.2.122 is | ✓ this code |
What each provider means by 5.2.122
A registered code does not oblige a provider to use it that way, and the large ones diverge. Match the wording in your own bounce, not the definition above.
Common causes of 5.2.122
- The recipient mailbox is receiving heavy traffic from many senders at once
- A shared or role address is subscribed to numerous automated systems
- A distribution list is delivering to a single mailbox at high rate
- The recipient is the target of a mail bomb or subscription flood
- Several of your own systems are writing to the same address independently
- A mailing list the recipient belongs to had a burst of activity
How to fix 5.2.122
- Do not suppress the recipient, since the address is valid and the limit is theirs
- Retry, since the limit is hourly and clears without intervention
- Consolidate your own systems if several of yours write to the same address
- Tell the recipient organisation, since only they can see the full picture
- For shared addresses, suggest a ticketing system rather than a mailbox
- Distinguish this from 5.2.121, which counts only your traffic