Postmaster : SMTP Error Codes

| // You can embed HTML in the text. The error codes should be unique, they'll be used to supply anchor tags from the top of the page. // *************************************************************************************************************************************************************************** $fd = fopen("./error-codes.template","r"); $i = 0; if($fd){ while($line = fgets($fd)){ $line_items = preg_split("/[|]/",$line); $code_array[$i][0] = $line_items[0]; $code_array[$i][1] = $line_items[1]; $code_array[$i][2] = $line_items[2]; $i++; } } else{ exit("Could not open template file."); } ?>

When sending email, you'll occasionally receive an error message with its own code. Here's an explanation of the codes—along with a recommendation on how to fix each error. Note: In the event you need to contact your email administrator, be sure to include the error message. It contains important information.

Choose the error message you received from the menu below:

\n"; echo "\n"; echo "

"; echo "

\n"; // this is for the static links /* echo "

" . $code_array[$i][0] . "

\n"; */ //output the actual content for ($i = 0 ; $i < count($code_array) ; $i++ ){ echo "

" . $code_array[$i][0] . " :: " . $code_array[$i][1] . "

\n"; echo $code_array[$i][2] . "\n"; } ?>

Non-Specific Error Codes

Error Code Returned	For more information
421 - [Too many sessions opened]	Comcast allows 25 simultaneous connections per sending IP address. This error results when that limit is exceeded.
421 - [Reverse DNS failure : Try again later]	Comcast requires all sending IP addresses have a valid rDNS. This error results when the lookup failed. This error should be treated as a temp-fail and can be retried. SERVFAIL response. 99.9% means that the DNS somewhere up the auth tree is misconfigured or down or very badly overloaded.
421 - [Try again later]	This error results for several reasons. This error should be treated as a temp-fail and can be retried.
452 - [Too many emails sent on this session]	Comcast allows 1000 emails per session. This error results when that limit is exceeded.
452 - [Too many recipients for message]	Comcast allows 100 recipients per message. This error results when that limit is exceeded.
550 - [Not our customer]	This error results when a message is sent to a non-existent Comcast customer. These errors should be treated as an "unsubscribe" by the sender, if a bulk mailer.
550 - [Your message could not be delivered due to too many invalid recipients]	This error results when a message is sent to too many invalid recipients. As a result none of the recipients received the message. Please check your distribution list and resend.
550 - [Invalid sender domain]	Comcast requires that all sending domains have a valid A or MX record. This error results when neither record can be found.
550 - [Account not available]	This error results when a message is sent to a Comcast account that is currently not available.
552 - [Message size exceeded]	Comcast allows messages of 15MB or smaller. This error results when that limit is exceeded.
554 - [PTR lookup failure]	Comcast requires all sending mail server IP addresses have a valid PTR record set up. This error results when the lookup failed. NXDOMAIN response. One of the authoritative servers for the relevant section of the in-addr.arpa DNS tree is saying that there is no PTR record for the given IP address.

Understand email error messages and their codes

Introduction

Non-Specific Error Codes