Sending Limits External and Internal 300 messages and 30 Messages Per Minute?

[Floyds_on_Greenwood]

I want to clarify the outcome/results for the following message sending limits.

When a user sends more than 300 external emails in a day-

They will be blocked. Is this correct?

When a user sends more than 300 emails to internal recipients within their tenant in a day-

They will be blocked. Is this correct?

If the aggregate of internal and external emails exceeds 300 in a day -

The user will be blocked from sending.  Is this correct?

When a user sends more than 30 messages within one minute to internal recipients within their tenant - individual users-

They will be blocked and will need to resend.  Is this correct?

When a user sends more than 30 messages within one minute to external recipients:-

They will be blocked and will need to resend.  Is this correct?

If the aggregate of internal and external emails exceeds 30 messages within one minute -

The user will be blocked and the messages will need to be resent.  Is this correct?

Thank you

[#2]

@Floyds_on_Greenwood 

Please refer this:

Exchange Online limits - Service Descriptions | Microsoft Learn

[#3]

Thanks for the KB. I have been reviewing that and thus - asked the question here to clarify.
This is how I interpret the KB:
Recipient limit: This is the maximum number of recipients allowed in the To:, Cc:, and Bcc: fields for a single email message.
--KW: This is a DAILY (24 hour period) aggregate for all email recipients internal or external that are addressed as a recipient in an email(s). The daily recipient limit is not configurable and is set at a maximum of 300 by Microsoft. Tenant/Global DL's are a considered a single recipient, personal DL's are the sum of the aggregate of their membership.

KW Message Rate Limit: This is the maximum number of messages that can be sent in one minute (60 seconds). This is the sum of the aggregate of internal or external recipients. The message rate limit is not configurable and is set to a maximum of 30 messages per minute (60 seconds) by Microsoft.
Note
For the purposes of the recipient rate limit and the recipient limit, a distribution group that is stored in the organization's shared address book counts as one recipient. In a personal distribution list, each recipient is counted separately.

Recipient proxy address limit: The recipient proxy address limit is the maximum number of aliases (email addresses) that a recipient mailbox can have.

Note One:
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.

Note Two (in conflict with note one):
footnote #4 When outbound message volumes surpass the message rate limit, any excess in message submission will be throttled and successively carried over to the following minutes. This will typically not block the sender's account, but Exchange Online isn't suited to accommodate bulk-mailing scenarios. For this use case, options 2 and 3 here are recommended instead.

[#4]

Greetings,

Re: Outlook sending limits

I want to report back on the clarification I have received from Microsoft support.

Sending an email to global distribution list created in the O365 Tenant / Active Directory is considered a single recipient.
Sending an email to a personal distribution list created in a user’s contact list – is the aggregate of the recipients contained within.


• Sending Limits External and Internal 300 messages and 30 Messages Per Minute? Yes

• When a user sends more than 300 external emails in a day-They will be blocked. Is this correct? Yes

• When a user sends more than 300 emails to internal recipients within their tenant in a day-They will be blocked. Is this correct? Yes

• If the aggregate of internal and external emails exceeds 300 in a day -The user will be blocked from sending. Is this correct? Yes

• When a user sends more than 30 messages within one minute to internal recipients within their tenant - individual users- They will be blocked and will need to resend. Is this correct? Yes

• When a user sends more than 30 messages within one minute to external recipients: - They will be blocked and will need to resend. Is this correct? Yes

• If the aggregate of internal and external emails exceeds 30 messages within one minute -The user will be blocked and the messages will need to be resent. Is this correct? Yes
I hope this adds clarification.