Are there limits or caps on the number of emails that can be sent from an O365 Mailbox?

Iron Contributor

Environment: Office 365 Education - Hybrid Exchange and AD

We have recently migrated one of our key admin assistants to Exchange Online. A process she has always undertaken now appears to fail.  (Noted: it's not the greatest process!!)


She copies and pastes ~600 email adresses into her new Message BCC Field (Outlook 2016 desktop client)  and sends it (To:) to herself.

It used to work when she was on-prem - it now fails.


I have read in other forums that there are limits set on O365 Online mailboxes for different licenses.  can anyone here confirm?


Thanks.. C

1 Reply

The recipient limit is 500. This is documented in the Exchange Online service limits, here. Mail merge, or using a DG, may be an alternative solution.