UNDERSTANDING WHY EMAILS SENT TO VALID EMAIL ADDRESS CAN STILL BOUNCE

Bounces due to Content

While we regularly check our Lists for invalid email addresses, an email can bounce even when the recipient’s address is valid and deliverable, simply due to the content of the message and these types of bounces are beyond our control. Many email servers employ advanced anti-spam filters that evaluate the email’s content – such as text, images, or links – and block messages that appear suspicious or are flagged as spammy. Factors that may trigger content filters include:

• Spammy language: emails with excessive promotional language, overuse of exclamation points, or certain flagged keywords can be rejected by spam filters.
• Suspicious links or attachments: links to blacklisted websites or attachments containing harmful files may cause your email to bounce.
• Improperly formatted HTML: poorly structured HTML emails, or messages that contain hidden text, can trigger content filters.

 Authentication Failures

Emails can bounce when they fail to pass authentication protocols such as SPF, DKIM, or DMARC – which are essential for verifying that the email is legitimate and hasn’t been tampered with during transit. If your domain is not properly authenticated, the recipient’s server may reject your email as a security precaution, resulting in a bounce. Again, these types of bounces are outside of our control.

• SPF (Sender Policy Framework) verifies whether the IP address sending the email is authorized to send on behalf of your domain.
• DKIM (DomainKeys Identified Mail) attaches a digital signature to your emails, verifying that the content hasn’t been altered. Learn more about how DKIM works.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance) provides a policy to ensure that emails failing SPF and DKIM checks are rejected or marked as spam.

IP Address Problems

Other bounces can occur  if the IP address of the sender has a bad reputation, even though the recipient’s email address is valid. This is another reason to use the services of a first class email delivery services such as Clickback.

Using an inappropriate Email Delivery System or Service

Some email services do not allow you to send cold emails. See the Sending Email page via the top Menu Bar for more details