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E-Mail Sending Limits

Arkansas State University applies email sending limits to help protect university accounts, university data, and A-State email systems from phishing, credential compromise, spam, and unauthorized mass email activity.

Overview

Microsoft has announced upcoming enforcement of additional Exchange Online sending limits, including external recipient rate limits. In addition to Microsoft Office 365 service-level limits, A-State may apply role-based sending limits to certain account types.

At this time, A-State is implementing sending limits for student accounts only. Employee-specific limits for faculty and staff accounts may be implemented in a future phase.

Current A-State Sending Limits

Account Type Internal Recipients Per Hour External Recipients Per Hour Total Recipients Per 24 Hours Status
Students 250 250 500 Effective 6/29/26
Employees (Faculty & Staff) Subject to Microsoft Office 365 service limits Subject to Microsoft Office 365 service limits Subject to Microsoft Office 365 service limits Future Phase

Who is affected right now?

The current A-State role-based sending limits apply to student accounts.

Faculty and staff accounts are not included in the current A-State role-based implementation. Employee accounts remain subject to Microsoft Office 365 service-level sending limits and any applicable security controls.

Why are these limits in place?

These limits help reduce the impact and spread of phishing, credential harvesting, spam, and other malicious email activity. They also help protect A-State accounts and preserve the reputation of university email systems.

What happens if I exceed one of the limits?

If an email would cause an account to exceed one of the sending limits, the message may fail to deliver to recipients. The account may also be restricted from sending additional email until the activity is reviewed.

  • The email may fail to deliver to all recipients.
  • The account may be restricted from sending mail.
  • An alert may be generated for IT Security review.
  • Account access may be temporarily blocked if the activity appears malicious or indicates account compromise.

Will I receive an error message?

In many cases, the sender may receive a delivery failure notice for messages sent after the account has been restricted.

The error may include wording such as:

  • Sending email address not recognized as a valid sender
  • 550 5.1.8 Access denied, bad outbound sender

What should I do if my account is restricted?

If your account has been restricted from sending email, contact the ITS Help Desk for assistance.

ITS Help Desk
Email: itshelpdesk@astate.edu
Phone: 870-972-3933

What if I need to send email to a large group?

Student email accounts are not intended for mass email distribution. If you need to send messages to a large group, you should work with the appropriate university department, faculty member, advisor, or administrative office to determine the appropriate communication method.

  • Departmental communication channels
  • Approved university email distribution lists
  • Canvas announcements or course communications
  • Other approved university communication platforms

Can an exception be granted?

Exceptions to student sending limits are not routinely granted. Any request for an exception must have a valid university business or academic purpose and must be sponsored by an appropriate A-State department or administrative office.

Microsoft Office 365 service-level sending limits still apply and cannot be overridden by A-State.

Microsoft Exchange Online sending limits are available in Microsoft’s official documentation: Exchange Online limits

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