Microsoft 365 - Email/Calendar Maximum Recipient Limits
This document answers questions related to the maximum email/calendar recipient limits within Microsoft 365.
What happens if I send more than my daily limit?
If you exceed your daily email sending limit you will receive a bounce back message that will contain the following error message:
How do I unblock my account?
Once you have exceeded your daily sending limit you will need to wait until the next day to send email. This is a Microsoft limitation and there is no way to unblock your account.
What counts against my sending limit?
- Email: Each recipient listed in the To:, Cc: or Bcc: fields of emails you send counts towards your sending limit.
- Calendar Invites: Each recipient of a calendar invite that you create counts towards your email sending limit
- Send As: Messages you send using the Send As feature count toward your account and not the account the From address is assigned to.
- Send on Behalf: Messages you send using Send on Behalf of permissions count toward your account and not the account you are sending on behalf of.
- Message Failures: Even if a message fails to be delivered, it still counts toward your sending limit.
What does NOT count against my sending limit?
- Forwarded Messages: If you have a forward set on your account the forwarded messages do not count against your sending limit.
- Inbox Rule Redirects: If you have an inbox rule that redirects mail to another account the forwarded messages do not count against your sending limit.
- Automatic Replies: If you have an Out of Office message configured, the replies do not count against your sending limit.
- Campus Relay: Emails sent via the campus relay service do not count against an account’s daily sending limit.
- 3rd Party Services: Email sent from other services using UW-Madison email addresses do not count. (example: Salesforce, Slate, Constant Contact, Mailchimp, Eloqua).
What happens when creating a calendar meeting which fails to send
If you create a calendar meeting that results in a failed delivery bounce-back notice, the event will not appear on any of the attendee’s calendars, but it will still appear on the organizer’s calendar.