Office 365 mail sending limits

Adrian Date 6

I understand that Office 365 has a max of 30 emails sent per minute. If I send 40 in a minute, what happens to the extra 10 emails ? Are they held and sent next minute time frame or are they just lost ?

Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2021-02-08T06:30:06.317+00:00

Hi,@Adrian Date
In addition, If you would like to give a feedback on this feature, it is recommended to vote or comment on Uservoice: Increase 30 messages per minute limit

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Kael Yao-MSFT 37,496 Reputation points Microsoft Vendor

2021-02-12T00:53:21.88+00:00

Hi, @Adrian Date
Just checking in to see if above information was helpful. Please let us know if you would like further assistance.

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Jaswant Vijayakumar 1 Reputation point

2022-07-28T05:59:34.407+00:00

Hi @Andy David - MVP

Same scenario from our end, we use the monitoring application to send the error device email to the respective team around 60 to 100 per minute. due to this some critical error alerts are missing and so if there is any feature/option to increase the email count more then a 50 per minute let us know or and any suggestion is highly appreciated.

1 answer

Andy David - MVP 142.2K Reputation points MVP

2021-02-07T00:16:45.303+00:00

If you are referring to the SMTP client sending limits ( does not apply to Outlook Web Access or Outlook in "Exchange" mode), then if that limit is exceeded, the messages over the limit are rejected:

Message rate limit: Message rate limits determine how many messages a user can send from their Exchange Online account within a specified period of time. This limit helps prevent over consumption of system resources by a single sender. If a user submits messages at a rate that exceeds the limit via SMTP client submission, the messages will be rejected and the client will need to retry.

https://learn.microsoft.com/en-us/office365/servicedescriptions/exchange-online-service-description/exchange-online-limits#sending-limits-1
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2 people found this answer helpful.
Adrian Date 6 Reputation points

2021-02-07T00:23:22.517+00:00

Thanks Andy. I thought so but hoped not.
I use a CMS that sends automatically emails and needs an smtp service. Obv my Office 365 would make sense but we do send more that 30 at a time sometimes especially when we are generating certificates for students. We swapped to an smtp relay service but that doesn’t allow the ‘email to SMS’ service our system also uses. Ahhhhhh

Andy David - MVP 142.2K Reputation points MVP

2021-02-07T13:06:18.84+00:00

Yea, messages that exceed limits are outright rejected when those limits are hit.

If you could, please mark an answer as accepted so we can close this up. Thanks!

Kumari, Nivedita 1 Reputation point

2021-10-13T19:37:10.017+00:00

Hi Andy,
Our team also ran to the same issue where we are looking for the message limit to increase from 30 email per minute.
Our application needs to send atleast 300 email per minute and wanted to know how can this limit be increased.
Any pointer is highly appreciated.
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