Knowledge base
The connection could not be madecriticaldelivery stateTCP connection to the receiving server failed or timed out.The destination could not be resolvedcriticaldelivery stateNo address could be found for the destination; the result field says whether the address is to blame or our own resolver is.The sender was refusedcriticaldelivery stateThe receiver refused our envelope address before the recipient was mentioned.The content was judgedcriticaldelivery stateThe verdict after the whole message was transferred — the state a successful delivery also carries.The recipient was refusedcriticaldelivery stateThe receiver refused the recipient address — unknown, full, disabled — before any content was sent.The sending address could not be usedimportantdelivery stateThe engine could not bind to the local address it was told to send from.The transfer was refusedimportantdelivery stateThe receiver refused the DATA command, before any content was sent.The extended greeting was refusedimportantdelivery stateThe receiver rejected our EHLO — often the first place a reputation problem shows.Processing the jobimportantdelivery stateThe job itself could not be processed — malformed, incomplete or otherwise unusable.Stopped by the suppression listimportantdelivery stateThe message was not sent because its recipient or domain is on the suppression list.The TLS handshake faileddelivery stateEncryption could not be established with the receiving server.The connection went quietdelivery stateAn established connection stopped responding while the message was in flight.The greeting never camedelivery stateThe receiving server accepted the connection but did not greet us in time.Personalisation faileddelivery statePlaceholders could not be filled from the message's data.A rewrite rule faileddelivery stateA rewrite rule could not be applied to the message.The upgrade to TLS was refuseddelivery stateThe receiver refused or failed the STARTTLS command.Unclassifieddelivery stateThe engine could not place the failure in any stage.Authentication statesdelivery stateRepresentative of the six authentication states, which occur only when sending through a smarthost.The plain greeting was refuseddelivery stateThe same refusal as ehlo, on a server too old for the extended greeting.Responsive Email rendering faileddelivery stateA message given as a specification could not be turned into MIME.The body could not be fetcheddelivery stateThe external message store could not return the body in time.