The vast majority of the emails we send arrive successfully in your customers' inboxes. 

But there are a variety of reasons why an email may not get delivered.

When a bounce does happen, you or someone on your team should take one of the following actions:

  1. Find a better point of contact at the company
  2. Correct a misspelled email address
  3. Possibly cancel their subscription if they aren't responsive

Your team can be notified when bounces happen in Churn Buster via Webhooks, Slack alerts, or through any of 750+ apps via our Zapier integration. You can set those up in your Integration Settings.

Bounce Types

When we notify you of a bounce, we'll include the type of bounce it was. The action you should take will vary based on this. i.e. You'd respond to a temporary delivery issue differently from a spam complaint.

Hard Bounce:
The server was unable to deliver your message (ex: unknown user, mailbox not found).

Message Delayed:
The server could not temporarily deliver your message (ex: Message is delayed due to network troubles).

Unsubscribe Request:
Unsubscribe or Remove request.

Subscribe Request:
Subscribe request from someone wanting to get added to the mailing list.

Auto Responder:
Automatic email responder (ex: "Out of Office" or "On Vacation").

Address Change:
The recipient has requested an address change.

DNS Error:
A temporary DNS error.

Spam Notification:
The message was delivered, but was either blocked by the user, or classified as spam, bulk mail, or had rejected content.

Open Relay Test:
The NDR is actually a test email message to see if the mail server is an open relay.

Unable to classify the NDR.

Soft Bounce:
Unable to temporarily deliver message (i.e. mailbox full, account disabled, exceeds quota, out of disk space).

Virus Notification:
The bounce is actually a virus notification warning about a virus/code infected message.

Spam Challenge Verification:
The bounce is a challenge asking for verification you actually sent the email. Typcial challenges are made by Spam Arrest, or MailFrontier Matador.

Invalid Email Address:
The address is not a valid email address.

Spam Complaint:
The subscriber explicitly marked this message as spam.

Manually Deactivated:
The email was manually deactivated.

Registration Not Confirmed:
The subscriber has not clicked on the confirmation link upon registration or import.

ISP Block:
Blocked from this ISP due to content or blacklisting.

An error occurred while accepting an email through the SMTP API.

Processing Failed:
Unable to deliver inbound message to destination inbound hook.

DMARC Policy:
Email rejected due DMARC Policy.

Template Rendering Failed:
An error occurred while attempting to render your template.

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