Easy Tips You Need to Know to Avoid Email Bounce

An astonishing 215.3 billion emails are sent per day [1]. If you’re like most companies, you probably want taking advantage of email marketing or use email to create a Facebook custom audience for sponsored posts. Searchbug’s Email Batch Append service has certainly gained popularity for these marketing tactics.

All you need is a list of names and cities, a phone number, or mailing addresses to upload, and Searchbug can work to append an email address to your list. That sounds simple enough, but that’s only the first hurdle of email marketing.  Now, let’s talk about how to get to the inbox!

When an email is undeliverable, digital marketers call it an email bounce. There are many reasons for an email bounce and contrary to common belief an invalid email address isn’t even the #1 reason.  Surprised?  Well, so was I.

I used to send myself ebooks via a throwaway email service. However, no matter how much I tried, some of my messages would not get to my inbox. I know my email address is valid.

Was it something I was doing? I had a simple university email that was impossible to mess up. Could the throwaway email service be faulty? I tried another service with no luck. Finally, I called the university’s tech support.

“We blocked those companies from sending emails to us because of spam complaints.” A tech informed me, the soft click of keys filling the background. “Yahoo, Gmail, and Hotmail aren’t on the block list, though. Try one of them.”

Before that moment, I had no idea someone could block messages from an email provider. Intrigued, I decided to ask the Computer Science department for some help. If nothing else, I learned one thing:  Email is more complicated than people think.

How does an email bounce happen?

As I stated above, there are many reasons for email to bounce. While an invalid email is one reason, here are a few others:

Blocked IP Address

Sending too many messages from a single IP address is a good way to earn a spot on the block list. Nobody likes spam, and most email providers strive to minimize it for their customers. You can actually block a specific IP address or an IP address range.


A blacklist is a registry of IP addresses and domains that often send spammy looking messages. A blacklist is a tool that helps filter out spam messages from someone’s inbox. To see your IP address blacklist status check out Barracuda or MXToolbox.

ISP Spam Filters and Blocks

Believe it or not, there is a list of rules that will determine when or if your messages reach an inbox. Poor content quality, certain words or phrases, and clear spam tactics will get you caught by them.

User Set Filters

Nobody likes spam, but 84% of all email sent is spam. Most users create filters and blocks to pinpoint spam and trash it or block it altogether.

Inbox Full

There are two types of people in this world: those that read their mail, and those that collect their mail. In the case of the latter, your message will definitely get kicked back. There’s only so much space an inbox has to store messages before you have to start trashing them.


Most email providers will give you a vacation setting. It’s different from a normal filter or block because it’s scheduled to expire on a set time and date. Many people use vacation messages when away from email for any length of time. These are sent to anyone that sends them messages.

Sender Reputation

There are several factors that make up your sender reputation. Most people won’t be aware that they have a reputation until there’s an issue with it. Learning what your reputation is and working to improve it is a good way to get your messages into an inbox.

Invalid Email

Last, but not least, is an invalid email address. Some people switch email addresses like others swap out winter gear or drink soda. Searchbug has a free validation tool to help you with this problem.

How do I avoid email bounce?

If you were hoping for an easy button, nobody’s invented that yet. Dedication and hard work are still best, but here are some helpful tips:

Trickle in New Emails

I understand that adding to your email list is exciting, especially if you have a small list to begin with. You want to send messages to your expanded list all-at-once, but know and realize that it’s a bad idea. That’s a spammer, and we want to avoid that, right?

Trickle in new email addresses little by little. Purchasing an email list doesn’t guarantee everyone on it wants what you have to offer. Keep that in mind when sending messages to a newly expanded list. Be sure you are following the CAN SPAM ACT accordingly otherwise you’ll have bigger problems and none of your email will be delivered.

Each time you send a new message, add 10% to 15% of those new emails to your current list. Measure engagement and keep only those emails that are interested in your product.

Send Messages at a Slower Pace

Mass emailing a large subscriber list is a bad idea, especially for larger lists. Not only does it cause errors, but it could get you flagged and marked as a spammer. Message a small percentage of your list every day until you’ve finished the list.

Never message them all at once.

Send Messages on a Schedule

Sending messages on a set schedule is a good way to establish a routine. It conditions people to expect your correspondence and increases the likelihood of engagement. Think of it this way:

How successful would the Sunday newspaper be if it rarely arrived on Sunday?

Use Double Opt-In

If you’re building your list via sign-up forms, using a double opt-in is a must. Not only do you verify a person wants to subscribe, you also show a measure of respect for user privacy. It’s also a good way to clean up your list, preserving your sender reputation.

Don’t Email to Clean Your List

Any subscriber list will decay over time. Keeping up with that decay is hard, especially for larger subscriber lists. Email verification services exist, but most are sub-par or expensive.

No matter how much you want to, never email your list to clean it up. That is a quick way to tarnish your sender reputation. Some email providers will suspend your account for it, too.

Be Careful With Your Keywords

Some industries are more scrutinized by mail providers and spam filters. If your message contains keywords that hit their radar, you’re more likely to get blocked. These keywords include:

  • Payday
  • Cash Advance
  • Loan
  • Money
  • Finance
  • Credit Score
  • Work from Home
  • Freebies
  • Pills
  • Dating

Any keyword relating to beauty or weight loss products are filter words. If you want your emails to go through, it’s best to avoid these and similar keywords.

Work With Different Email Providers

Every email provider is different. Their tolerance for sending emails to a subscriber list is different, too. Some will allow it (up to a point) and others don’t. If you happen to run afoul of an email provider, having two or three more to shift your list to is helpful.

Searchbug uses and recommends Mailchimp.

Read, Understand and Follow the CAN-SPAM ACT

Believe it or not, this is actually a law that governs commercial email. Failure to follow these guidelines could lead to a fine of up to $16K for every email that violates the law. Here is a summary of them:

  • Don’t deceive people.
  • Make unsubscribing easy.
  • Include your real contact information
  • Never send without consent

If you’re an honest business, these guidelines should be easy to follow. You can read more on their website.

Personalize Your Messages

You receive a letter in the mail addressed to you. You have no idea who it is, but the letter is for you. Do you open it or toss it away? If you’re most people, you’re going to open it.

You want to know what it is. More importantly, you want to know who it is. The internet is no different, and this is how people will treat personalized messages.

What are you doing to avoid email bounce?

There are many ways to avoid email bounce, and everyone has a different take on it. What tactics have worked for you? Leave us comments and questions below!


Here are some websites and tools to help you increase the success of your email campaigns:


  1. The Radicati Group, ING. Email Stats