Email bounces: why they happen & how to handle them?

Email bounces are a common occurrence, and understanding why they happen is crucial for maintaining a healthy sender reputation.¹ Here’s a breakdown of why emails bounce and how to handle them:

Understanding Email Bounces

An email bounce occurs when an email cannot be delivered to the intended recipient and is returned to the sender. These bounces can be categorized into two main types:²

• Hard Bounces:
  • These indicate a permanent delivery failure.³
  • Common causes include:
    • Invalid or non-existent email addresses.⁴
    • Domain name issues.⁵
    • The recipient’s server permanently blocking the sender.⁶
  • These are the most damaging to your sender reputation.⁷
• Soft Bounces:
  • These indicate a temporary delivery failure.⁸
  • Common causes include:
    • Full recipient mailbox.⁹
    • Temporary server issues.¹⁰
    • Email size exceeding the recipient’s server limit.¹¹
    • Temporary server outage.¹²
    • The receiving server’s security filter temporarily blocking the email.

Reasons Why Emails Bounce

Here are some of the most common reasons:

• Invalid Email Address:
  • Typos in the email address.¹³
  • The email account no longer exists.
• Server Issues:
  • The recipient’s email server is down or experiencing problems.¹⁴
  • The sender’s email server is experiencing problems.
• Mailbox Full:
  • The recipient’s inbox has reached its storage limit.¹⁵
• Spam Filters:
  • The email content triggers spam filters.¹⁶
  • The sender’s IP address is blacklisted.
• Email Size:
  • The email exceeds the recipient’s server’s size limit.¹⁷
• Authentication Issues:
  • Problems with SPF, DKIM, or DMARC records.¹⁸

How to Handle Email Bounces

Here’s how to address email bounces:

• For Hard Bounces:
  • Immediately remove the email address from your mailing list.
  • Repeatedly sending emails to hard bounce addresses can damage your sender reputation.¹⁹
• For Soft Bounces:
  • Try resending the email after a short period.
  • If the soft bounce persists, remove the email address from your active list.²⁰
  • Investigate the reason for the soft bounce if possible.
• Maintain a Clean Email List:
  • Regularly verify email addresses.²¹
  • Use double opt-in for new subscribers.
  • Remove inactive subscribers.
• Improve Sender Reputation:
  • Authenticate your emails with SPF, DKIM, and DMARC.²²
  • Avoid sending spammy content.²³
  • Maintain a consistent sending volume.
• Monitor Bounce Rates:
  • Use email marketing tools to track your bounce rates.²⁴
  • Identify and address any trends.

By understanding the causes of email bounces and taking appropriate action, you can improve your email deliverability and maintain a positive sender reputation.²⁵