March 10, 2021
2 mins read

Reasons why your email address is blocked

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Sometimes it may have happened to you that you send an email to a person and that email doesn’t reach the destination mailbox. The message is blocked. This article explains some of the reasons that may occur so that a sent email is not received in the recipient’s email address.

Browsing the Internet you immerse yourself in a world of protocols and servers. We find protocols such as HTTP, HTTPS, FTP, TCP, IP, SSH protocol, DNS protocol, etc.. These protocols allow communication of different systems. By another band we have servers such as web servers, mail servers, proxy servers, VPN servers, etc.. Servers are computers that serve requests from clients and return a response. We’re going to focus on mail servers.

Your emails are being blocked

You have a company that sends emails through a corporate domain. You realize that some of those emails don’t reach their recipient. The main reason these emails are filtered and blocked is because someone categorizes them as spam content.

A real example of what happens is the case I present below. You create a website and host content on it, but at some point a cybercriminal introduces malware into that content. You don’t realize it at first. One day you get a message from a service provider or even the company that provides you with the accommodation and tells you that you have a folder with pirated content. You delete that folder, you check that everything’s okay and you don’t go around anymore. However, days later you verify that when you send mail through your Page’s domain these messages are filtered and don’t reach their recipient.

How to know if your emails don’t arrive and is blocked

You want to send an email to your customers and that email had a link to the domain that was affected by cybercriminals. Most emails were sent correctly. There are several tools that let you know if an email has been bounced and returned.

The returned e-mails (Bounces) are messages that, due to some error, could not be delivered to their respective recipients. The eMail Bounce Handler program is capable of processing messages returned from all kinds of sources such as from your personal files, your local and remote mailboxes or simply from text dragged as is to the application or pasted from the clipboard.

You can integrate Bounce Handler into EasyMail7  to process bounces. In that case you can see that there may be emails blocked by spam filters like  Barracuda  and  FortiGuard and they come back. The reason would be “Spam Content”.

Fighting spam

At first glance in our own mailbox we have very easy to identify spam emails: you don’t recognize the email address that comes in the From field. As you probably know, the main reason emails are filtered is content that looks like spam. It seems because there may be false positives, emails that end up in spam but are not spam.

It is easy to recognize spam emails with the naked eye. You have an unknown email address in the From field. The misspelled matter. Subject lines written ALL SHIFT. Large font size and often in bold, purely promotional and sales content.

Also, have you ever paid attention to the links you use in your emails? You can think about why you should worry about bindings if they’re from your own domain. I thought the same thing until recently that I discovered that links can be a cause of email blocking. If your email message contains links from blocked domains, you have the “possibility” to filter or block.

Spam blacklists

If your domain has been exposed and has been spamming without your consent, it may be blacklisted and that’s why some filters block your email as spam. There are websites like that inform you if an IP address or domain is considered a source of spam. Mail server operators may or may not use that information to classify or block the email core you send.

The website  a list of 94 well-known online blacklists. Just put your domain in and see if any of those blacklists are your Page. If you are… that may be one of the reasons why your emails don’t reach their recipient.


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Avelino Dominguez

👨🏻‍🔬 Biologist 👨🏻‍🎓 Teacher 👨🏻‍💻 Technologist 📊 Statistician 🕸 #SEO #SocialNetwork #Web #Data ♟Chess 🐙 Galician

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