This time we want to approach the topic from a perspective closer to marketing and sales teams.
In more down-to-earth language, we’ll go through the reasons behind each bounce and, perhaps more importantly, what we can do (if anything can be done, which isn’t always possible) to rescue that subscriber from their failed bounced status and bring them back as an active subscriber and, therefore, a potential customer or reader of our communications.
For a more structured overview, we’ll use the table of bounces and reasons already presented in the article mentioned above, with a more detailed description of the reasons and a new column of possible solutions or actions.
Important: Mailrelay doesn’t publish the exact number of retries or campaigns involved in bounces.
We need to understand how a subscriber is marked as bounced, and for that we have to distinguish between a hard bounce and a soft bounce:
- Hard bounce: the destination server has bounced the message permanently, so no more emails are sent to that address.
- Soft bounce: when the destination server has bounced the email with a temporary error. After a soft bounce there are several retries, and emails can still be sent to the address until it is marked as a hard bounce.
| Error code | Error message | How to try to fix it | ||
| bad-configuration | The messages were rejected due to configuration issues on the remote server. This is a problem with the destination server: it has an error in its settings and doesn’t allow messages to be received. | We should call the subscriber so they can ask their system administrator to fix it and let us know once it’s done, so we can tell Mailrelay. | ||
| bad-connection | The messages bounced due to connection issues with the remote server. In other words, the sending server can’t reach the destination domain properly because of a fault somewhere along the intermediate connection path. | The problem here may have nothing to do with the destination server and instead lie with one of the intermediate servers. Ideally, we should contact the administrator of the destination server to report the problem, and also our internet provider so they can look into where the problem may be. | ||
| bad-domain | Messages bounced due to invalid or non-existent domains. In other words, the recipient’s domain doesn’t exist. | We should check that the address we’re sending to is correct and call the subscriber so they can ask their system administrator to fix it and let us know once it’s done, so we can tell Mailrelay. | ||
| bad-mailbox | Messages rejected due to an incorrect, invalid or non-existent recipient address. The destination email account doesn’t exist. | We should check that the address we’re sending to is correct and call the subscriber so they can ask their system administrator to fix it and let us know once it’s done, so we can tell Mailrelay. | ||
| content-related | Messages rejected for content-related reasons (possible spam, sender added to blacklists, etc.) | We need to check that we’re following every point in the article “tips to keep your newsletter from being considered spam“. We should contact the administrator of the destination server to report the problem and look at possible solutions. Finally, you can contact our Customer Support team to analyze the problem in depth. | ||
| inactive-mailbox | The messages were rejected because the recipient accounts have expired or are inactive or disabled. In short, something similar to the error where the destination email address doesn’t exist. | We should check that the address we’re sending to is correct and call the subscriber so they can ask their system administrator to fix it and let us know once it’s done, so we can tell Mailrelay. | ||
| message-expired | The message was not delivered within the maximum retry period allowed. | We can resend the message at a time when the sending queue is less congested. | ||
| no-answer-from-host | The messages bounce because no response is received from the remote server after connecting. This is a configuration problem on the remote server. | We should contact the administrator of the destination server to report the problem and look at possible solutions. | ||
| other | The messages were rejected for other reasons | We should contact the administrator of the destination server to report the problem and look at possible solutions. | ||
| policy-related | The messages were rejected or blocked for policy reasons. Usually spam policies. | We need to check that we’re following every point in the article “tips that will keep your newsletter from being considered spam“. We should contact the administrator of the destination server to report the problem and look at possible solutions. Finally, you can contact our Customer Support team to analyze the problem in depth. | ||
| protocol-errors | Messages rejected due to SMTP protocol syntax errors. Mailrelay always uses correct syntax and commands, but there may be an interpretation problem on the destination server. | We should contact the administrator of the destination server to report the problem and look at possible solutions. | ||
| quota-issues | Messages rejected or blocked due to quota issues. The server rejects the message because the destination mailbox is full. | We should call the subscriber so they can ask their system administrator to fix it and let us know once it’s done, so we can tell Mailrelay. | ||
| relaying-issues | Messages rejected or blocked due to delivery issues on the remote server. There can be various reasons stemming from the destination server’s internal administrative policies, for example not accepting any email from its own domain that doesn’t come from its own IP. | We should contact the administrator of the destination server to report the problem and look at possible solutions. | ||
| routing-errors | Messages bounced due to routing issues on the recipient’s domain. In other words, the sending server can’t reach the destination domain properly because of a fault somewhere along the intermediate connection path. | The problem here may have nothing to do with the destination server and instead lie with one of the intermediate servers. Ideally, we should contact the administrator of the destination server to report the problem, and also our internet provider so they can look into where the problem may be. | ||
| spam-related | Messages rejected or blocked for spam-related reasons. There is some problem with the sender configuration, the message content or spam complaints that causes our messages to be blocked. | We need to check that we’re following every point in the article “tips to keep your newsletter from being considered spam“. We should contact the administrator of the destination server to report the problem and look at possible solutions. Finally, you can contact our Customer Support team to analyze the problem in depth. | ||
| virus-related | Message rejected or blocked for reasons related to computer viruses. This can be problematic. It mainly happens when we attach a file that contains a virus or could potentially contain one, for example Excel or Word files. | The solution is to scan the files we attach with an antivirus and, if the problem is that the destination server rejects them because they could potentially carry viruses, zip them first or simply use this method to send a download link instead. | ||
We hope you find these tips useful.
Related posts:
To better understand this problem, find out exactly what a bounce is and how the bounce rate of your campaigns is calculated.