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Trubbleshooting bouncing Emails

Trubbleshooting bouncing Emails

This guide helps Windows users identify the most common reasons for email delivery issues and how to fix them.

Common reasons why emails bounce

  1. Incorrect email adress

    • One of the most common causes is a typo in the recipient’s email adress

    • Double check for errors like @hotmial.com instead of @hotmail.com

    • Avoid using characters like å, ä, ö in email addresses, they may not be supported in all systems

  1. Recipient’s inbox is full

    • You may see an error like “Mailbox full” or “Quota exceeded”

    • This is not your fault, the recipient needs to clear space in their inbox

 

  1. Blocked by spam filters

    • Your email may be flagged as spam, especially if:

      • It contains many links or large attachments

      • The subject line is in all caps or uses excessive punctuation

      • It includes suspicious or “spammy” keywords

 

  1. Problem with recipient’s domain

    • The domain, e.g., @company.com, may no longer exist

    • Or their mail server might be temporarily down

 

  1. Issues with your own email configuration

  • If all your outgoing emails are bouncing (not just one), you may have an issue with your own account setup

Contact your IT-Support!

What you can check yourself

Read the bounce message

Look for codes like 550, 552, 554. These can help you identify the problem:

  • 550 5.1.1 = Recipient doesn’t exist

  • 552 5.2.2 = Inbox full

  • 554 5.7.1 = Blocked due to spam rules

 

Test with another recipient

  • Try sending a message to another address

  • If that email goes through, the issue is likely with the original recipient

  • If it also bounces, check your own setup or internet connection

Tips to avoid email delivery issues

  • Don’t send large attachment directly (<25 MB), use OneDrive etc.

  • Use a simple subject line. Avoid ALL CAPS, emojis, or too many exclamation points

  • Don’t put too many recipients in the “To” field, use BCC for bulk emails

  • Make sure you’re not sending too many emails in a short time, that can trigger spam filters

Need further help?

If you’ve gone through all steps and still have issues:

  1. Save the bounce message

  2. Contact your IT support or email provider

  3. Attach the full error message so they can investigate further