My Email Bounced: What an Undeliverable Message Means

Got a "Delivery has failed" or "Undeliverable" message after sending an email from your NCU account? Learn what the error code means and what to do next.

Got a "Delivery has failed" or "Undeliverable" message back after sending an email from your North Central University account? The message tells you why. Here's how to read it and what to do next.

Find the reason

Open the bounce message. Near the bottom, under Diagnostic information for administrators, look for a code like 550 5.1.1. Match it to the table below.

Code	What it means	What to do
5.1.1 or 5.1.10	The address doesn't exist.	Check the spelling. If it looks right, ask the person for their current address.
5.2.2	The recipient's mailbox is full.	Try again later, or reach them another way.
5.2.3 or 5.3.4	The message is too large.	Remove the attachment and share a OneDrive link instead.
5.7.1	You aren't allowed to send to that address. Some distribution lists only accept mail from certain senders, and some people block senders.	Contact the list owner or the person another way.
5.1.90	You reached your daily sending limit.	Wait 24 hours. See Email Sending Limits at NCU.
5.1.8	Your account has been blocked from sending, usually because of unusual sending activity.	Call the IT Service Desk right away. Your account may be compromised.
Starts with 4	A temporary problem. Outlook keeps trying.	Wait. You'll get a second message only if it finally fails.

Bounces for email you didn't send

Spammers can fake your address, so you may get bounces for messages you never sent. Check your Sent Items folder:

• The messages are in Sent Items: someone may be using your account. Follow What to Do if Your Account is Compromised and call IT now.
• The messages aren't there: your address was likely faked. Don't open attachments or links in the bounces. You can delete them or report them as phishing.

Get help

Still bouncing? Submit a request through Microsoft Office 365 E-mail & Calendar and include a screenshot of the full bounce message.

Still need help? Call the IT Service Desk at 612.343.4170 or visit Miller Hall 226, Monday–Thursday, 7:30 a.m.–9 p.m.; Friday, 7:30 a.m.–4:30 p.m. CT.