10 Reasons Why Emails Bounce & the role of Email Verification

Email bounces appear when emails are not accepted by the internet service provider or business email server for that address. When that happens, a code is returned to let you know that the message in question was rejected. There are multiple types of bounces, mainly soft or hard. The hard bounces are permanent and they show you are not allowed to send the message ever again. Soft bounces, on the other hand, show that it’s just a temporary issue and more often than not you need to keep trying.


You will even receive an error code too. The 421 error code means the service is not available. The 500 code, on the other hand, means that the address does not exist. Or 516 means that the mailbox has moved. It’s very important to understand the meaning of every code and actively figure out the reason behind its appearance. This way you can at least identify the reasoning behind the issue and how you can address it. Yet you have to wonder, why do emails bounce?

Spam filters are very aggressive

Around 84% of all email is spam, so the problem is clear, spam filters do end up being aggressive. And that means messages can end up blocked or bounced even if they shouldn’t. Let’s face it, this type of situation does appear especially if you have advertising related messages and people have their email service block messages with certain words. This is definitely one of the main reasons why emails tend to bounce rather often.

Industry standards evolve

There’s a lot of email abuse and that’s why you will notice many companies starting to increase their focus on creating clean and proper emails. Organizations like Agari, Comcast, Google, and Yahoo are actively focused on eliminating email abuse naturally and they do everything they can to eliminate all that potential hassle at their own pace.

Blacklisted IPs

Seeing blacklisted IPs is rather normal nowadays and spam filters will check the sending IP against the blacklisted ranges. If the reputation is bad or the IP was blacklisted, more often than not the messages in question will be bounced. That doesn’t mean it’s a bad thing to think about, but the outcome is definitely very tricky. Repeat offenders will be blacklisted, so trying to boost your reputation and staying away from the list of blacklisted IPs is a priority!

Sender reputation

And that all adds up to sender reputation. Just as the receiver, the sender also needs to have a good reputation as well. The idea is that the sender reputation is monitored based on many factors and it’s linked to the IP address or the domain. If the reputation is not that good, then the emails can be bounced.

Invalid addresses

This is actually very common. If you send to a recipient address that doesn’t really work the way you want, then it’s a good idea to see if it’s valid or not. There are fake addresses designed to capture and steal data, so make sure that an email address is valid before you use it. After all, the last thing you want is to deal with any problems, and the more you think about it and use it adequately, the better it will be for you in the end.

Temporary undeliverable

There are times when a server will reject emails due to a few issues. The email might be too large, you might not be able to connect properly or the inbox is full. All these things are obviously a problem and they will stop you from completing the task. That’s when emails will bounce. Sometimes the server will try to resend the emails in a few hours, but for the most part, you need to try and do that yourself.

Natural base decay

Many times email addresses end up being not available because those persons are not a part of the company anymore. If an email is disabled it’s easy to see that there will end up being problems, all you have to do is to find the right approach and system, then actively focus on finding the best way to connect with the person in question.

Server administrators check every email

There are situations when someone might not receive the message because the server administrator has to manually check every email. That can be a huge task to take, especially in the case of a large business. But with so many attacks and potential problems that might appear, you never want to take anything for granted. Which is why double checking even under this kind of situation is a crucial aspect to keep in mind and it will surely be an important aspect!

The email is blocked by the server

This can also happen, the server is blocking emails due to a few internal factors. It’s hard to know when that happens. Not to mention it can be strange to encounter such an issue because you barely know the reason. Yet it does happen more often than not and all you have to do is to either call that person or use another email address. It’s not a massive problem unless this is the only address you had for contact.

The recipient is blocking your emails

Of course, there are also situations where the recipient is actively blocking messages from you. That definitely ends up happening more often than not, and it’s something that you have to consider. If you reply or send messages and you receive only errors, this might very well be the reasons why emails bounce.

If you want to solve the problem, one of the best ways to do that is to verify your email. Verified emails don’t bounce because they are known to not contain any spam or unwanted things. It’s a very good idea to show your legitimacy in the online world. And it will also make it easier for you to eliminate any potential problems that might appear more often than not. Don’t hesitate and verify your email as quickly as possible to avoid any email bounce!