Have you ever run into the SMTP bounce message "too old"? Perhaps with a status code of 602? Here's what that means!
This isn't an SMTP rejection code enshrined in the RFC covering email rejection and deferral codes. Instead, it's a Mailgun-specific message disposition response offered up by their platform after the Mailgun platform has attempted to deliver the message for a period of time, and hasn't been able to deliver the message successfully, in that time, after numerous attempts.
In some other systems this might show as "message expired." Certain platforms will just log the 4xx error code (temporarily deferral response) as the final bounce when logging disposition for a given message. (Meaning you might end up with a message's bounce information showing a "soft bounce" or "deferral" for what has effectively become a permanent rejection.) Regardless of how they log it, it all means the same thing: Something impeded delivery of that specific message for so long that the sending platform has given up and is no longer attempting to deliver the email message in question. They've logged it as undeliverable and moved on.
This means that the sending platform's MTA (mail server) was either unable to connect to the receiving mailbox provider's MTA (trying multiple times, unsuccessfully), or every time it did manage to connect, it received a temporary deferral error response (4xx error) and was told "sorry, can't accept your message now, try again later." (This rejection message of "too old" doesn't give you enough information to tell you why the deferral was happening. Was it a spam/reputation issue? Was the receiving mailbox provider having a system issue? There's not enough information here to know.)
How long until a message is considered "too old"? Per this Mailgun help page, eight hours. Other email service provider and marketing automation platforms may try for a different amount of time; various platforms handle these things differently. It is perhaps common for many platforms to expire (give up on) these messages after 72 hours.
Have you ever run into the SMTP bounce message "too old"? Perhaps with a status code of 602? Here's what that means!
This isn't an SMTP rejection code enshrined in the RFC covering email rejection and deferral codes. Instead, it's a Mailgun-specific message disposition response offered up by their platform after the Mailgun platform has attempted to deliver the message for a period of time, and hasn't been able to deliver the message successfully, in that time, after numerous attempts.
In some other systems this might show as "message expired." Certain platforms will just log the 4xx error code (temporarily deferral response) as the final bounce when logging disposition for a given message. (Meaning you might end up with a message's bounce information showing a "soft bounce" or "deferral" for what has effectively become a permanent rejection.) Regardless of how they log it, it all means the same thing: Something impeded delivery of that specific message for so long that the sending platform has given up and is no longer attempting to deliver the email message in question. They've logged it as undeliverable and moved on.
How long until a message is considered "too old"? Per this Mailgun help page, eight hours. Other email service provider and marketing automation platforms may try for a different amount of time; various platforms handle these things differently. It is perhaps common for many platforms to expire (give up on) these messages after 72 hours.
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