Update 7/14/2025: Updated the FAQ.
As with all cloud services, Exchange Online imposes service limits to prevent misuse of Exchange Online resources and ensure availability for all users. For examp...
Updated Jul 14, 2025
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Hi First off i agree with most of you in here, that these Limits are way to low in the real world, if you run a business where sell products and use MS for just some of those transactions then you will run in to problems fast.
I have some questions too that i can not see being asked:
I a Hydrid Setup where Onprem Exchange send's all mails out via Online Exchange how will that effect the counting? i did find some answers here: https://practical365.com/tenant-wide-external-recipient-rate-limit/#comment-307838
But please elaborate Microsoft
The so-called Mass mail service MS has put in place is IMO a joke when looking at the limits for external recipients and the prises, it looks like MS actually want's us to move to a different provider!
The limits you have set here, how did you come up with those?
KevinShaughnessy
Microsoft
MicrosoftKarstenV59 RE Hybrid: yes if they're going to external recipients (address that are NOT part of an accepted domain in the tenant) those will be counted. From the FAQ:
Are messages to external recipients that are relayed through my tenant from my on-premises environment counted against the quota?
Yes. All messages sent outbound to external recipients from your tenant qualify for counting against your tenant’s quota, regardless of whether they originate from on-premises, from Exchange Online mailboxes, or from the Internet.
As for ACS email, the limits are readily upgradeable via a support ticket. You can find instructions/form to fill out here: Quota increase for Azure Email Communication Service - An Azure Communication Services concept document | Microsoft Learn
Thanks for clarification, as 2 the part 2 of your answer Im aware that we could upgrade the ACS if we had one ;-) but ACS is just not the answer for the problem you at MS have created for us by limiting external recipients we can send mails to.
We will take this up with our local Account manager at MS, we will then see where it goes.