Summary: Bounce Codes & Reasons

Anonymous
Not applicable

Summary: Bounce Codes & Reasons

There are a lot of questions on the Community on bounces. I thought it would be nice to share this list with you, which I found on the internet.

What is a Bounce?

A bounce is basically a rejected email. When you send your campaign, When the email gets to the receiving server (where your subscriber’s email is located), the receiving mail server either accepts the email or rejects it. The rejection is called a Bounce.

There are 2 types of bounces: Soft and Hard.

Soft Bounce

A soft bounce normally happens when the receiving Mail Server is temporarily unable to receive the email.  There are several reasons why this would happen.   The following are reasons for soft bounces.

  •   A server is unavailable or it’s down
  •   The server is overloaded
  •   The recipient’s mailbox is full
  •   Your message size is too big

Soft bounces would normally resolve itself.

Hard Bounce

A hard bounce is more permanent. 

There are several reasons why an email would hard bounce. The main characteristic though, is that it is a permanent rejection. Below is a list of bounce codes that's available.

   

     Bounce code

  
   

     Bounce type

  
   

     Description

  
    5.0.0    Hard    Address does not exist
    5.1.0    Hard    Other address status
    5.1.1    Hard    Bad destination mailbox address
    5.1.2    Hard    Bad destination system address
    5.1.3    Hard    Bad destination mailbox address syntax
    5.1.4    Hard    Destination mailbox address ambiguous
    5.1.5    Hard    Destination mailbox address valid
    5.1.6    Hard    Mailbox has moved
    5.1.7    Hard    Bad sender\’s mailbox address syntax
    5.1.8    Hard    Bad sender’s system address
    5.2.0    Soft    Other or undefined mailbox status
    5.2.1    Soft    Mailbox disabled, not accepting messages
    5.2.2    Soft    Mailbox full
    5.2.3    Hard    Message length exceeds administrative limit.
    5.2.4    Hard    Mailing list expansion problem
    5.3.0    Hard    Other or undefined mail system status
    5.3.1    Soft    Mail system full
    5.3.2    Hard    System not accepting network messages
    5.3.3    Hard    System not capable of selected features
    5.3.4    Hard    Message too big for system
    5.4.0    Hard    Other or undefined network or routing status
    5.4.1    Hard    No answer from host
    5.4.2    Hard    Bad connection
    5.4.3    Hard    Routing server failure
    5.4.4    Hard    Unable to route
    5.4.5    Soft    Network congestion
    5.4.6    Hard    Routing loop detected
    5.4.7    Hard    Delivery time expired
    5.5.0    Hard    Other or undefined protocol status
    5.5.1    Hard    Invalid command
    5.5.2    Hard    Syntax error
    5.5.3    Soft    Too many recipients
    5.5.4    Hard    Invalid command arguments
    5.5.5    Hard    Wrong protocol version
    5.6.0    Hard    Other or undefined media error
    5.6.1    Hard    Media not supported
    5.6.2    Hard    Conversion required and prohibited
    5.6.3    Hard    Conversion required but not supported
    5.6.4    Hard    Conversion with loss performed
    5.6.5    Hard    Conversion failed
    5.7.0    Hard    Other or undefined security status
    5.7.1    Hard    Delivery not authorized, message refused
    5.7.2    Hard    Mailing list expansion prohibited
    5.7.3    Hard    Security conversion required but not possible
    5.7.4    Hard    Security features not supported
    5.7.5    Hard    Cryptographic failure
    5.7.6    Hard    Cryptographic algorithm not supported
    5.7.7    Hard    Message integrity failure
    9.1.1    Hard    Hard bounce with no bounce code found. It could be an invalid email or rejected email from your mail server (such as from a sending limit).

 

As a note, the bounce codes displayed on this list are the codes that servers receive from the receiving mail servers. It is important to know that it’s possible that these mail servers may provide codes that do not really reflect the true nature of the bounce.

9 REPLIES 9
Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Excellent overview and compilation of error codes!
Itay_Billet4
Level 8

Re: Summary: Bounce Codes & Reasons

Awesome, thanks Diederik!
Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Is there anywhere in Marketo that you can see the bounce codes / reasons? I currently have a pretty high hard bounce rate (for external purchased lists) but our soft bounce rate is even higer. 

Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Try checking this field: Email Invalid Cause.
Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Great work in compiling this list Diederik!
Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Is there a way to filter or create a list based on the code?

Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Thanks Diederik, very helpful!
Anonymous
Not applicable

Re: Summary: Bounce Codes & Reasons

Hi,
I am wondering if you happen to have a suggested course of action for these codes.  I took your codes and tried to categorize them (bad content - opportunity to improved, non-working email - no future action/delete record from Marketo).  Do you happen to have something like this?

I want to be sure I am managing the database properly when it comes to bounces.  Deleting those that are truly bad and identifying any opportunities to either improve the content or our email campaigns so as to not trigger spam alerts.

Thank you,
Kerry
Tom_Patterson
Level 2

Re: Summary: Bounce Codes & Reasons

Brilliant overview, thank you for sharing!