Why your emails are bouncing back and how to solve it

We’ve all been there before, you’ve spent an age crafting out the perfect email campaign only to receive that dreaded notification within minutes of sending it out into the wild. Whichever synonym it has arrived by this time, ‘failed, bounced, rejected’, receiving an email with those overly negative subject lines can be disheartening and confusing - especially when you’ve no idea what you did wrong in the first place.

Worse, even when a reason for your email bouncing back is provided, it is often an unintelligible block of tech speak. 

Luckily, most of the issues that cause bounce backs won’t require you to send out a frantic call to your IT department, or for smaller businesses, call out computer support, nor will they take too long to fix, eating into your busy work schedule.

Let’s run through some of the basic, and a little more complex, reasons why your emails are bouncing back and provide you a little clarity on how to solve them.

What does an ‘email bounce back’ mean?

In basic terms, to send an email requires two things, the sender and the recipient; when you hit send on that important email, your mail server attempts to locate the intended recipient’s mailbox on their mail server, in order to transfer the message. If for some reason that connection or transfer fails, your mail server should notify you and this, is the bounce back email, subject: failure to deliver. 

And it happens more than you’d think, last year it was found that across the globe, over a fifth of commercial emails never reached the intended recipient.

So far, so good. 

The real problem lies in diagnosing where exactly in the process it went wrong, and deciphering the block of numbers and letters your computer has spat back out at you is no easy feat.

But, armed with a careful eye our handy phrasebook, you’ll be fluent in email jargon in no time.

Why are my emails bouncing back?

The majority of the time, the reasons your emails are bouncing back are caused by something you can easily fix;

Email Address Errors

Sometimes it’s literally as simple as just a mistyped or misspelled email address, something easy to overlook, or perhaps the email address you’re trying to connect with is a little outdated. Always make sure to proofread your email addresses, as even a dot one character too early can cause an address error, and try to fact check your contact list beforehand.

Lack of Storage 

Occasionally your email simply hasn’t got enough space to land, or is taking up too much space in the first place. 

Perhaps your intended recipient has exceeded the storage set by their provider; either try sending to a different mailbox, or connect over an alternate mode of communication. 

Similarly, if you’re trying to send an attachment, sometimes it can be too large for your recipients mail server to handle, although most of the time, you should be notified of this prior to sending. If possible, try and reduce the file size, or, if not, you can easily use an online host like dropbox and share the document using a secure invitation. 

Sometimes, however, there are trickier issues at play, that may take more time to solve.

Permission Denied

This means the recipient's mail server mistakenly thinks you’re spam, or malware, and is protecting itself by refusing to accept any of your content. To solve this, you’ll need to contact whoever manages your mail server, or hosts your email address, as somewhere along the line your mail server could’ve got a bad reputation.

In this case, the bounce back you receive may look like this:

joe@theemailrecipient.com SMTP error from remote mail server after end of data: host mail.destinationserver.com [12.62.3.52]: 554 Service unavailable; Client host [smtp.myhostingco.com] blocked using name of company here; http://www.nameofcompany.com/reputation/?r=1&ip=12.62.3.52

One thing you can do as a preventative measure, or if you begin to receive these bounce backs, is check, and tighten, both your email and your wi-fi’s security through virus scanning software and by regularly updating your passwords. 

Read more about how to protect your computer from cyber attacks

Sender Address rejected: Relay Access Denied

This usually means that you’re trying to send from an email address that is not allowed on the mail server you’re trying to use, as in, you’re entering the ‘from’ address examplename@gmail.com but using your Internet Service Provider’s mail server instead of Google’s.

The message could not be sent because the server rejected the sender's e-mail address. The sender's e-mail address was (Email address). Subject (Subject), Account: (Account name), Server: (Server name), Protocol: SMTP, Server Response: '505 Authentication required', Port: 25, Secure(SSL): No, Server Error: 505, Error Number: 0x800CCC78

What do Email Error Codes mean?

One of the most common, and baffling, features of email bounce backs are the error codes.

The error code itself refers to Simple Mail Transfer Protocol (SMTP) code generated out of a range of numbers between 400-499, and 500-599, respectively, each correlating with a specific reason why your email is not sending.

The SMTP error codes are split into two categories; a temporary failure and a permanent (although not unfixable) failure, some of which we’ve already run through above.

Temporary Failures: 400 Errors

A failure between the 400’s means that either the target server is down and not accepting connections, or that the server is temporarily refusing to accept the mail, but might accept it later. Excluding many free, or bulk email providers, mail servers will usually try for up to 5 days before giving up. After 4 hours, a notice is normally sent back to the sender explaining why there is a delay; at the end of 5 days, a final delivery failure message is sent back to the sender.

This primarily happens when a server is too busy, or the recipient’s mailbox is too full.

Permanent Failures: 500 Errors

‘Permanent Failures’ mean that the mail server will not accept the delivery of this message and it should be returned to sender. Despite the name, these bounce backs usually have simple solutions, some of which are detailed above, including misspellings or email address errors, however 500 Errors can also encompass servers that have had their permission denied.

Despite its exactitude, there are times when email can and will fail, whether it is simply a case of human error, or a technical misunderstanding, hopefully our quick scan of the basics will ensure you’re able to mitigate the amount of bounce backs you receive, and ensure your email account is running as smoothly and efficiently as possible.

Evolvit deal with these kinds of issues daily. If you'd like to speak to one of our team about ongoing IT support services for your business then please get in touch. 

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