When delivery of an email message fails, the mailbox provider sends our email system a code combination of numbers and text to indicate a soft or hard failure. We organize these codes into failure reason categories to help you understand and correct the problem.
Note: Depending on the Blackbaud application you use — such as Blackbaud Internet Solutions or Blackbaud NetCommunity — failure information is available in reports. For information about how to view this data, refer to the application's user documentation. If failure information isn't available in your application's reports, contact Support for assistance with issues related to specific mailings or email addresses.
A hard bounce occurs when a mailbox provider rejects an email message, such as if the recipient email address does not exist.
Note: To ensure a positive sender reputation, our system automatically suppresses email addresses that return hard bounces from future mailings.
A soft bounce occurs when an email message is processed by the recipient's mailbox provider but is returned as undeliverable before it reaches the recipient.
A block failure occurs when an email recipient's mailbox provider intentionally refuses a message, such as if the sending IP address is on an external blacklist or the SPAM complaint rate for the sender is high.
A technical failure occurs when delivery to an address or domain fails due to difficulties that occur during the attempt to connect with the recipient's mailbox provider.
Learn about soft failures that result from blocks by receiving mailbox providers and how to correct them.