Maybe it’s happened to you, one day your email is working fine and the next it’s not. You didn’t do anything, so how did your website suddenly go from reliably sending email to not. I’m regularly asked this question.

Trust me, I’d love to wave a magic wand and get rid of all your email woes. Unfortunately, I can’t.

The issue is that for your emails to get delivered they have to interact with literally hundreds of servers and thousands of filters.

And to add more complexity, these filters change literally every day. This is why things can suddenly stop working. They suddenly stop working because the filters changed.

Prefer to watch this article as a video? I’ve got you covered:

Why is it so hard to get email past filters?

Because of spammers.

Every year spammers get better at getting through spam filters, so the spam filters, in turn, get tougher for everyone to get through. This is why approaches that worked in the past to deliver email suddenly stop working.

The top spam filters are updated constantly and are personalized to each account based on that account’s behaviors. This is why you may reach some people at a domain but not others.

Personal email providers like @gmail, @yahoo, @aol, etc all make it much harder to get past their filters. Additionally, the owners of these personal accounts are usually clueless about how filters work.

How does email get from sender to recipient?

Let’s talk about the journey of a typical email (simplified some):

  • An email is created and sent (by a person, by an app, by a website, etc).
  • The email looks on the internet look for the recipient’s server.
  • It hopefully finds the recipient server and delivers the email to there.
  • The recipient server is a lot like a mail room. A piece of mail arrives and has to be sorted before delivery to a final destination.
  • The recipient server looks at all of the sorting rules and decides where to deliver it. This could spam folder, person’s inbox, or elsewhere.
  • In the email world, these sorting rules are frequently called filters.

How email filters work

Most email server’s filters (or sorting rules) are constantly changing. Literally, with almost every single email that they receive and how the account holder treats that email.

Account holders who don’t understand filters can easily take actions which have unintended consequences. For example, if they delete the first two emails you ever send them, that tells the filter you don’t want to read emails from that sender.

What are the possible things a filter can do with your email?

  • Deliver it to the inbox
  • Put it into a folder (Gmail Promotions)
  • Put it into Spam
  • Put it into Spam Quarantine
  • Delete it
  • Bounce it
  • Forward it somewhere else (yes, you then go through the whole process all over again)

Email filters have become increasingly complex and also increasingly stubborn. They generally learn to treat something as spam much easier than to treat something as desired.

Once an email filter starts to dislike an address, it will usually dislike everything from that address. Once they get in a habit, they are very hard to break of that habit (personal email providers like @gmail, @yahoo, @aol, etc are the most difficult).

This is why it’s a good idea to have different email addresses for different purposes. Many businesses will have a website address for just website related emails, a marketing address, a billing address, a general inquiry address, etc.

Getting past the filters: types of email

There are basically 3 types of email:

  • Marketing: Items like email newsletters where one person is sending to many. These may be automated through email newsletter provider.
  • Transactional: Automated emails, typically from a website or app. Where the website is sending to just one person. This is emails such as thank you for filling out a form, purchase receipt from eCommerce.
  • Direct: These are the emails that one person sends to specific people. For example, most of your business correspondence, emails between coworkers, questions from customers.

How do I get my email delivered to the inbox?


  • Have a dedicated email address for marketing, so if the filters decide it is spam, your other messages may get through still. Some companies take this a step further and use a separate domain for marketing only emails.
  • Use an email newsletter provider and make sure it’s connected to a real domain address (not @gmail, @yahoo, etc). Make sure to read the newsletter provider’s guidelines on maximizing deliverability.
  • Avoid known spam words in your emails:


  • Have a dedicated email address (same domain as your website)
  • Don’t use built-in mail() function (this is the default on most servers)
  • Make sure your email is authenticated (via OAuth or SMTP)
  • Use a delivery service (MailGun, SendGrid, SendinBlue, etc) – delivery services are basically an alternate way to get your email there. Delivery services act very similarly to how a courier service works in the real world for delivering physical mail.


  • Don’t send marketing emails from the addresses you use for direct email.
  • Make sure you are sending them through an email client (not a third party service).
  • Don’t include lots of links (even 3 links can be a sign of spam)
  • Don’t include large attachments (use for large attachments)

Some additional items for ALL email types – these are technical items and you should contact your email hosting provider or a developer for help with them. I don’t expect most website owners to have any idea what these are, and you don’t need to know.

Just know that they are important for your email delivery:

  • Make sure you have a DKIM record
  • Make sure you have an SPF record
  • Make sure you have an rDNS

Some additional items for ALL email types – these are non-technical items you can check yourself, and you should check every couple months:

  • Use to check if your domain has any blacklists
  • Check your reputation on
  • Check your reputation on and check website with URL scanner
  • Check your reputation with
  • Check your Google Search Console for any notices

Any other tips?

When someone signs up for something on your website (such as an email list subscription), make sure to give them a thank you message telling them to check their spam folder if they don’t see an email within a few minutes.

This might be the first email they are receiving from you, it may end up in spam. If they remove it from spam, that tells their inbox that they like this email.

It can take a couple of spam removals to train an inbox to like something (filters can be stubborn, especially those on personal accounts).

What about “white-listing”?

You may see a number of emails that ask you to “white-list” a particular email address or domain.

White-listing is basically telling your email service that you want to skip all spam checks on an email from the address and always deliver it to the inbox.

This is a great tool for getting emails into an inbox.

Unfortunately, very few people actually know how to white-list. Since so few people actually know how to white-list, this generally is useless and just creates more confusion with already confused people.

Key Takeaways

  • Every year email delivery gets harder.
  • What worked in the past may not work in the future.
  • There are three types of email: marketing, transactional, personal/direct.
  • Each email type should be handled differently for deliverability.
  • It’s important to check your domain’s black-list status and reputation regularly.
  • It’s always easier to get something marked as spam than to get it marked as not spam.


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