A Valid Email Address Just Bounced. Why?

An invalid email address is not the only potential cause for a message to bounce. There are many factors that can cause a message to bounce that are not directly related to whether or not the email address is valid or invalid.

Here are some examples of what can cause an email message to bounce:

• The recipient domain may have blocked your email address, IP address, or domain, but VerifiedEmail’s IP address was not blocked at the time of the verification.
• The email address is valid, but spam filters could be flagging your email message as spam.
• Your sender reputation could be low due to previous bounces and low engagement.
• The number of sent messages may exceed the rate limit indicated by the internet service provider (ISP).
• Your email domain/server might not be configured correctly to Request for Comments (RFC) Standards for internet messaging.
• Your mail service provider might not be configured to handle domains that use email greylisting.
• The recipient’s email domain may have deactivated the email address due to lack of use, but the address is still technically valid. For example, Google, Yahoo, and other service providers may undertake significant purge of inactive addresses. Some addresses like that might be successfully verified, but bounce on delivery.

All of these examples can cause your email messages to bounce even if the email address is valid.

To understand what is causing a bounce, you can access your Simple Mail Transfer Protocol (SMTP) logs and analyze the associated SMTP bounce codes. These are generally three-digit codes that have a universal meaning regardless of your email delivery service. Different mail service providers often have their own custom response codes, so be sure to investigate yours with your provider.