Understanding Email Bounce Backs: What They Mean and How to Fix Them

Sometimes when you send an email, you get a message back saying it couldn't be delivered. This is called a "bounce back" or "bounce message." It can be confusing, but it usually means something went wrong. Here's a simple guide to common reasons and what you can do:

Why Your Email Bounced (Reasons, Error Messages, and Solutions):

  • Reason: The email address is wrong (typo!).

    • What it means: You typed the email address incorrectly. Maybe you missed a letter, used the wrong domain (like "@gmial.com" instead of "@gmail.com"), or put in an extra space.

    • Example Error Message:

      • "User unknown"

      • "Invalid recipient"

      • "Domain not found"

      • "Address not found"

      • "550 No such user here"

    • Solution: Double-check the email address very carefully. Compare it to where you got it from. Correct any mistakes and try sending again.

  • Reason: The person's mailbox is full.

    • What it means: The person you're sending to has too many emails and doesn't have any room for new ones.

    • Example Error Message:

      • "Mailbox full"

      • "Over quota"

      • "552 Disk quota exceeded"

      • "Insufficient system storage"

    • Solution: Try sending the email again later. They might clear out their mailbox. If it keeps bouncing, try contacting them through another method (phone, text, etc.) and ask them to check their email storage.

  • Reason: The email address doesn't exist anymore.

    • What it means: The person has closed their email account or changed their email address.

    • Example Error Message:

      • "Account disabled"

      • "User account is unavailable"

      • "550-5.1.1 The email account that you tried to reach does not exist"

      • "No such mailbox"

    • Solution: Try contacting the person using another way (phone, text) to see if they have a new email address. If not, the email address is no longer valid.

  • Reason: The server blocked your email.

    • What it means: The email server that receives the email thinks your email is spam or harmful. This can happen if your email looks suspicious (lots of links, too many recipients, etc.).

    • Example Error Message:

      • "Blocked"

      • "Relay denied"

      • "Message rejected due to spam content"

      • "550 5.7.1 Message rejected due to content restrictions"

    • Solution:

      • Keep your emails simple. Avoid using too many links or attachments.

      • Make sure you're not sending spam-like emails. Don't send unsolicited messages to large groups of people.

      • Check your email's "Sent" folder. If you see the email there, it might have been sent successfully despite the bounce back. This can sometimes happen due to server hiccups.

  • Reason: A large attachment has been added.

    • What it means: The email has an attachment which is over the maximum permitted by the recipient's mail server

    • Example Error Message:

      • "Message too large"

      • "Attachment size exceeds allowable limit"

      • "552 Message size exceeds maximum permitted"

    • Solution:

      • Check your attachement size.

      • Compress attachments into a zip file

      • Use Sharepoint to generate a shareable link.