With so many prospects and customers relying on email to receive information about promotions, deals, events, and news to their inbox, companies are working harder than ever to build large email lists — but gathering valuable contact information is only half the battle. Spam complaints, undelivered messages, and unsubscribes can all impact email deliverability, as Internet Service Providers (ISPs), Email Service Providers (ESPs), anti-spam advocates, and email protection services set thresholds for bounced emails, spam complaints, and unsubscribe requests.

If your email marketing efforts are consistently being sent to invalid or unwanted email addresses, your messages are likely being filtered as spam, and your account is probably frequently being blocked. To ensure your messages reach their intended destination (the inbox), maintaining proper email hygiene is critical.

Keep reading to learn more about email bounce backs and what measures you can take to set up your organization for email deliverability success.

What Is a Bounce?

An email bounce occurs when an email is rejected by the recipient’s mail server. Upon rejection, the sender receives a notification that their email has not been delivered — or that it has “bounced” back.

Typically, bounce-back emails contain information detailing why the original message failed to send. Common examples include:

• The mail server that bounced the original email
• The time and date the message bounced
• An RFC code that helps explain the reason for the bounce (according to the RFC, hard bounces are indicated by a 5XX code and soft bounces by a 4XX code, though not all ISPs adhere to the same codes consistently, so there are exceptions to this rule)

Bounces are broken down into two distinct types:

Hard Bounce

Hard bounces are permanent reasons an email cannot be delivered. Addresses that result in a hard bounce are considered invalid and should not be sent further messages. There are many reasons a message can result in a hard bounce, but the most common examples are:

• The email address does not exist
• The recipient’s domain name does not exist
• The recipient’s email server has completely blocked delivery

Soft Bounce

Conversely, soft bounces are temporary reasons an email cannot be delivered. The email address is valid, and the message reached the recipient’s mail server; however, a delivery issue has prevented the message from reaching the recipient’s inbox. Once again, there are many reasons a message can result in a soft bounce, but the most common examples are:

• The recipient’s mailbox is full (the user is over their quota)
• The recipient’s email server is down or offline
• The sent message is too large for the recipient’s inbox

If an address continues to result in a soft bounce after several attempts in a 72-hour period, the address should be listed as unsafe for sending.

The Importance of Email Validation

A high percentage of emails expire each year because people either switch their address or update their account. It’s also common for customers to provide fake email addresses out of privacy concerns.

Invalid addresses on your email list can severely damage your brand. Even if invalid addresses constitute only 10% of your email list, there’s a good chance that only about 44% of your emails will get delivered if you’re not using an email validation service.

The potential consequences of a high bounce rate as a result of failing to validate email addresses are wide-ranging. You may get labeled as a spammer, ensuring that very few of your customers ever actually see your messages (and even fewer bother to read them). High bounce rates can also hinder your brand’s reputation. Some email service providers even ban clients with high bounce rates simply because they failed to validate their email addresses.

Bottom line: you need a reliable way to validate email addresses to help you avoid the consequences of a high bounce rate and ensure you’re reaching your customers with the right messaging at the right time — affordably, efficiently, and accurately.

When looking for a way to validate email addresses, focus your effort solely on services that include the features your business needs to succeed. For small businesses, this could be single-email address validation. For enterprises, bulk email verification is likely a better fit.

Take Action to Stop Email Bounce Backs

Although the email industry used to view hygiene vendors in a negative light because they made it appear senders were getting bad data, practicing good email hygiene habits is now considered a crucial element toward improving email deliverability.

To ensure quality email hygiene for our customers, Act-On currently partners with NeverBounce. This email verification and list cleaning service use a proprietary 20+ step verification process to check each email up to 75 times from different locations around the globe. Utilizing MX, DNS, SMTP, SOCIAL, and additional private technologies in determining the validity of addresses, NeverBounce guarantees that no more than 3 percent of valid emails will bounce after using their service. NeverBounce also offers free deduplication and bad syntax removal prior to cleaning to ensure error-free email lists.

Preventing bounce backs and ensuring quality data usage are just two necessary components of ensuring your emails are consistently delivered to the inbox. Check out our Deliverability 101 series to learn how your organization can prepare for (and achieve) email marketing success.