Bounce Categorization

Mailtrap categorizes bounces based on the responses from the recipients' MX servers.

The table below lists these responses and their descriptions. It also contains information on whether these bounces cause automatic suppression.

You can find bounce categories in the app, specifically in event history in Email Logs, Webhooks payload for bounce and soft_bounce events, and Suppressions for hard bounces.

Category	Event name	Description	Adding to Suppressions
transientfail	Transient failure	The email encountered a temporary issue.	No
greylisting	Greylisting	The email was temporarily rejected by the recipient's server to determine whether the sender was legitimate or not.	No
badsender	Bad sender	The email was rejected because the sender's address was invalid or unrecognized.	No
block	Blocked	The recipient's email server blocked the email, possibly due to security policies.	No
content	Content issue	The email content triggered content filters and was rejected by the recipient's server.	No
dnsFail	DNS failure	The email could not be delivered due to issues with the DNS configuration of the recipient's domain.	No
generalfail	General failure	The email could not be delivered due to a general failure on the recipient's server.	No
other	Other	The email was bounced for an unspecified or unknown reason.	No
relayfail	Relay failure	The email was rejected because the server is not allowed to relay messages.	No
serverfail	Server failure	The email could not be delivered due to a failure on the recipient's server.	No
spam	Spam detected	The email was identified as spam by the recipient's mail server.	No
verifyfail	Verification failed	The email was rejected because the sender's or recipient's addresses could not be verified.	No
timeout	Timeout	The email was bounced due to an unspecified issue, probably a timeout.	Yes
badrecipient	Bad recipient	The email was bounced because the recipient's email address is invalid or does not exist.	Yes
overquota	Over quota	The recipient's mailbox is full and cannot accept new messages.	Yes
serverpolicy	Server policy	The email was rejected due to the recipient's server policy settings.	No
spam_gmail	Gmail limitation	The email bounced due to limitations from Gmail recipient due to either incorrect authentication, sudden increase of email traffic, or reputation issue	No