Email Sending Limits

As of March 13, 2026, Purdue University student email accounts now have lower email sending limits. At this time Purdue staff & faculty accounts are still in the monitoring stage, but further testing will someday have lowered sending limits than the default Microsoft configuration.  This impacts the following Purdue campuses: PWL, PNW, PFW, & Purdue Indianapolis.

When users hit the sending limit, they will receive a bounce back email from Microsoft Outlook with the error message that includes:

550 5.1.8 Access denied, bad outbound sender

New Student Email Sending Limits

Purdue student accounts will be limited to:

  • 200 emails per hour
  • 500 emails per day

What If My Account Gets Blocked?

If you exceed the email sending limits, your account will be blocked from sending email. You can still receive and read emails, but while your email is blocked, you cannot send or reply until the block is removed.

How to Restore the Ability to Send Messages

To restore sending:

  1. Submit a ticket to Purdue IT Support
  2. Request that your email sending be unblocked

Once reviewed, IT Support can restore your account so you can send email again

Why the Change

Purdue IT is implementing this change to help combat the number of phishing emails sent in our environment. This change will greatly reduce the number of recipients and likelihood of Purdue users receiving a phishing email.

This change also aligns with Purdue University’s official Email Policy outlined here:

https://www.purdue.edu/vpec/policies/information-technology/s7/

Why This Happens

You’re most likely to hit a limit if you:

  • Send the same message to lots of people individually
  • Reply to large threads multiple times
  • Send automated or scripted emails

If you need to reach a large group, regular email is usually not the best option.

Better Options for Reaching Groups

Use a Listserv Mailing Lists

Mailing lists are the recommended way to email large Purdue audiences.

  • Designed for high-volume messages
  • Managed by list owners

Mailing lists must follow Purdue’s official guidelines:
https://service.purdue.edu/TDClient/32/Purdue/KB/ArticleDet?ID=509

Use Qualtrics for Surveys or Signups

If you’re collecting responses (events, surveys, feedback):

  • Utilize the Qualtrics platform to invite individuals to contribute to a survey, event, or provide feedback
  • Purdue supported and secure
  • Can be configured to include internal or external signups

For Homework and Lab Communication

Instructors/TAs: Please utilize Brightspace’s Announcement section to contact groups of students. Be sure to check the Send email copy box to ensure communication reaches your target audience as applicable. These emails come from the Brightspace platform themselves rather than your individual Purdue account.

The Communication tab and Class list section can also be used to email classmates or instructors; however, these emails are included in sending limits calculations.  

Can I Get an Exception?

Sometimes — but only for limited, approved cases. You may request an exception if the email is:

  • Official University business
  • Time sensitive

Student organization announcements and general mass emails usually do not qualify if a mailing list would work.

Contact Purdue IT Support with:

  • What you need to send
  • How many people
  • When it needs to go out

Which Option Should I Use?

What are you trying to do?

Best option

Why this works

Email a student org, class, or department

Brightspace / Listserv

Built for large groups and won’t hit your personal sending limits

Send an announcement to a defined Purdue audience

Listserv

Policy approved and managed by list owners

Run a survey or poll

Qualtrics

Secure, Purdue supported, and easier to manage

Email a student organization (greater than 100 members)

Listserv

Built for large groups and won’t hit your personal sending limits

Email a small group (under ~50 people)

Regular email

Unlikely to hit sending limits

Need to send a large, official, time sensitive message

Request an exception

Reviewed for limited, approved cases

Sending repeated reminders to many people

Qualtrics or Mailing List

Prevents hitting hourly/daily limits

 

Still Not Sure?

If you’re unsure which option to use, reach out to Purdue IT Support before sending repeated emails.

Email is not the only method of communication. Consider using social media platforms to also advertise and gather audiences.