5.2.122: recipient has received too many messages this hour
The Microsoft 365 recipient has hit the hourly limit on messages it can receive from all senders combined, so new mail is refused for now.
- Microsoft
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 5.2.122
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- Either side, depending on the cause. Start with the checks below that are yours.
- What the server says
5.2.122 Recipient's per hour message receive limit exceeded
What it means
This limit is counted at the recipient: the total number of messages a Microsoft 365 recipient can receive in an hour from all senders together. When it is reached, Exchange Online turns away further mail with 5.2.122, whichever sender it comes from. It usually points to a mailbox under a flood from a mail storm, a loop or a large automated feed. Senders should try again later and send less often; the recipient's admin can find the mailbox in the Mailboxes exceeding receiving limits report.
Common causes
- The mailbox is receiving a burst of mail from many systems at once.
- A loop or a misconfigured application is flooding the address.
How to fix it
- 01Retry later, once the hourly count has dropped.
- 02If you send automated mail to this address, reduce how often you send.
- 03Recipient admins: check the Mailboxes exceeding receiving limits report and stop the source of the flood.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Email nondelivery reports and SMTP errors in Exchange Onlinelearn.microsoft.com
Related codes
- 5.2.121Too many messages to one recipient this hour.The sender has gone over the number of messages Exchange Online lets one sender deliver to the same recipient within an hour.
- 432 4.3.2Recipient mailbox is receiving too fast.Exchange Online is slowing delivery to one mailbox because it is receiving too many messages at once; the sending server should retry later.
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