Microsoft Exchange for Business has defined email sending limits. Exceeding sending limits will cause the Exchange server to interpret your email as suspicious and potential phishing, preventing your email from sending. These limits apply to your personal UWSP email as well as any shared mailboxes you may help monitor such as a shared department mailbox.
See below for how to work within the two most common sending limits.
Per Email Limit
500 recipients maximum within a single email.
If a mailbox attempts to send to more than 500 individual recipients added in the To/CC/BCC lines in a single email, the email will not be sent and the mailbox will receive a Delivery Status Notification (DSN) email containing an explanation of the email failure.
Workaround: Divide the recipients between several emails making sure to stay below the 500 recipient limit.
Note: Exchange distribution groups that display in the Outlook Address Book count as a single recipient. Each recipient is counted separately in personal distribution lists.
24-Hour Period Limit
A total of 10,000 user accounts emailed in a 24-hour period.
If a mailbox surpasses the 10,000 messages per day limit, it will receive a Delivery Status Notification (DSN) message. No additional messages can be sent from that mailbox for 24 hours.
Workaround: Divide the email messages needing to be sent between two or more days making sure to stay under the 10,000 messages per day limit.
Contact the IT Service Desk with additional questions!