The heartbreak of having an email delivery failure is comparable to the heartbreak found in Hollywood dramas with sad endings. Add to that the fact that these “error messages” are not communicative, and you have a frustrating situation. While every email hosting server will have somewhat different messages and codes for its errors, this guide will provide the explanations for some of the most common mail delivery failure messages.

Delivery error—sometimes numbered 550 or 554. This is the most common error. It indicates that the email address in question does not exist, and therefore, no mail can be delivered to it. This error usually occurs because of a spelling error in the name of the recipient, a missing number or symbol, or some other mistake in typing the address. Just check the address and try again.

Unknown host—generally doesn’t have a reference number. This message indicates that 1) the domain name entered at the end of the email address was spelled incorrectly, 2) the domain name no longer exists, or 3) the domain name’s DNS settings have been set up incorrectly. Check the full email address for accuracy. If this doesn’t resolve the issue, contact the recipient to validate that the email domain name is current and correctly configured.

Mail not accepted—sometimes numbered 550 or 554. This indicates that the recipient’s account has been set up to restrict your email address, restrict anyone from your domain name, or restrict anyone but an approved group of people from sending messages to that email address. These settings will need to be altered to allow your message to arrive.

Service unavailable—sometimes numbered 550 or left unnumbered. This message generally indicates that the recipient’s email host is either not accepting email due to temporary volume issues or maintenance. Wait a few hours and try sending the message again.

Sender address rejected—sometimes numbered 550 or 554. This dreadful message means that your address has been declared a spam address by the email hosting group that the recipient uses. The best approach is to contact the email host directly and ask to have your name and address removed from the blacklist.

Inbox full—sometimes numbered 552 or left without a code. This error message indicates that the recipient has either reached the limit for the number of emails received during an allotted time frame or no longer has any inbox storage space remaining. The recipient will simply need to free up space so you can send the message.

Message exceeds maximum file size—sometimes numbered 552. This means that your attached files are larger than the maximum allowed by the email server. Send the email without the attachment, reduce the attachment size, or use an external file transfer service that works with your email.

There are many other email error messages that may come your way, and they can be harder to decipher than Mayan hieroglyphs. If you encounter a number or message not listed here, one good approach to researching the issue is to look for a help file provided by the recipient’s email service provider.

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Guest Post by Selena Narayanasamy: Selena loves all things technology, blogging, productivity, social media and caffeine. You can find her writing on her social/tech website Esvienne, or follow her on Twitter- @SelenaVidya

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