What does Mailgun's 'Too old' delivery status message mean and how to troubleshoot it?

Marketer from Email Geeks shares that he often sees these when there are reputation-based throttling issues and suggests checking Mailgun logs for the original bounce.

Email marketer from Reddit user, EmailNoob, answers that to troubleshoot 'Too Old' bounces, check your sending reputation, ensure your email content isn't triggering spam filters, and verify the recipient's email address is valid.

Email marketer from MailerQ states that when you get a bounce, you need to determine why the message could not be delivered to the recipient. There are several reasons for bounces that can occur when sending email. Some are related to the recipient address or domain. Other reasons are related to the reputation of the IP address, the configuration of your server, or the email content.

Email marketer from Mailjet answers that you can take the following steps to fix your bounces, confirm you have permission to send emails to recipients. Check that your subscriber list is up-to-date. Authenticate your emails. Improve your sender reputation. Monitor your bounce rate.

Email marketer from HubSpot shares that factors affecting email delivery, such as sender reputation, authentication, and content quality, can indirectly contribute to 'Too Old' bounces if they cause delivery delays or temporary failures.

Email marketer from Stack Overflow user, randomdev, shares that the 'Too Old' error often arises because the destination mail server was temporarily unavailable for an extended period, preventing delivery attempts from succeeding within the queuing timeframe.

Email marketer from Email on Acid shares that temporary email bounce codes can occur when the recipient’s inbox is full, the server is down or too busy, or the message is too large. While the server tries to deliver the message, after a certain amount of time, it may stop and send a “too old” message.

Marketer from Email Geeks adds that if temporary failures are not in Mailgun logs, there may be an internal failure, and the support team may be able to provide insight into internal logs, potentially related to connection issues.

Email marketer from SendGrid says that temporary bounce rates can occur because of problems with the recipient's server. If temporary errors continue for a period of time they might stop delivering the message, resulting in a delayed or “too old” message.

Marketer from Email Geeks explains that a 'Too old' message usually means there have been too many delivery attempts, causing the system to stop trying.

Email marketer from GlockApps shares that a high bounce rate can negatively affect your sender reputation, and suggests regularly cleaning your email list, using double opt-in, and monitoring your bounce rate to identify and address issues promptly.

Marketer from Email Geeks suggests it's possible the system couldn't establish a connection with the recipient mail server, leading to the message being dropped from the queue.

Email marketer from Email Delivery Forums shares that 'Too Old' errors often mean the message exceeded the maximum time it could remain in queue and suggests reducing email size, checking DNS records, and ensuring proper authentication.

Expert from Spam Resource explains that deferred messages are temporarily undeliverable. The server will attempt to deliver the message for a period, after which it may be returned to the sender with a 'Too Old' status if delivery fails. Common causes include the recipient's server being unavailable or too busy.

Expert from Word to the Wise answers blocking problems that lead to bounces, these could be caused by your IP or domain being blocklisted, or your DNS may not be configured properly, which causes delays and can result in 'Too Old' messages.

Documentation from RFC covers Standard SMTP Enhanced Status Codes. While there isn't a specific 'Too Old' code, it explains codes related to temporary failures (4xx) and permanent failures (5xx) which are useful to understand why a message might bounce or become 'Too Old'.

Documentation from Mailgun explains that the 'Too Old' status indicates that Mailgun attempted to deliver the message for a certain period (usually 72 hours), but the recipient server didn't accept it. This can be due to temporary issues on the recipient's side or a problem with the email itself.

Documentation from Amazon SES explains that bounces occur when an email cannot be delivered to the recipient. Hard bounces indicate a permanent delivery failure, while soft bounces suggest a temporary issue. Repeated soft bounces can eventually lead to a 'Too Old' status.

Documentation from Oracle explains that a permanent failure indicates that the email address is bad, or the email server rejected the message. A temporary failure indicates that the email server is unavailable or experiencing issues, which can result in delayed delivery and a 'Too Old' status if the issue persists.