SmtpStatusCode

SmtpStatusCode enumeration (32 values)

Smtp status codes

ValueDescription
NotDefinedNot defined
GeneralFailureGeneral failure
SystemStatusSystem status, or system help reply. A SMTP status 211 is a message that gives details about the Mail Server status. In the case of a System Help reply, it is a message to the user requesting help information.
HelpMessageA help message for a human reader will follow. SMTP 214 is usually provided as a response to the “HELP” command. A user will usually receive this as a displays of information about the mail server and it will most likely be in the form of a link to the FAQ page of THAT particular SMTP software that is running on the mail server. Due to the nature of this error and how the email server responds, it is normally called a reply, as in SMTP Reply 214.
ServiceReadySMTP Service ready.
ServiceClosingTransmissionChannelService closing transmission channel
AuthenticationSucceededAuthentication Succeeded
OkRequested action taken and completed.
UserNotLocalWillForwardThe recipient is not local to the server, but the server will accept and forward the message.
CannotVerifyUserWillAttemptDeliveryThe recipient cannot be VRFYed, but the server accepts the message and attempts delivery.
Base64ResponseText part containing the [BASE64] encoded string
StartMailInputStart message input and end with. This indicates that the server is ready to accept the message itself
ServiceNotAvailableThe service is not available and the connection will be closed.
PasswordTransitionNeededA password transition is needed
MailboxBusyThe requested command failed because the user’s mailbox was unavailable (such as being full). Try again later.
LocalErrorInProcessingThe command has been aborted due to a server error. (on their side)
InsufficientStorageThe command has been aborted because the server has insufficient system storage.
ClientNotPermittedClient does not have permission. TLS not available due to temporary reason. Encryption required for requested authentication mechanism.
CommandUnrecognizedThe server could not recognize the command due to a syntax error.
SyntaxErrorA syntax error was encountered in command arguments.
CommandNotImplementedThis command is not implemented.
CommandNotPermittedСommand is not permitted during a mail transaction
UnrecognizedAuthenticationTypeUnrecognized authentication type
AuthenticationRequiredThe SMTP server requires a secure connection or the client was not authenticated. But sometimes it’s about the recipient’s server blacklisting yours, or an invalid email address.
AuthenticationMechanismIsToWeakAuthentication mechanism is to weak
CredentialsInvalidAuthentication credentials invalid
EncryptionRequiredRequestedMechanismEncryption required for requested authentication mechanism
MailboxUnavailableIt usually defines a non-existent email address on the remote side.
UserNotLocalTryAlternatePath“User not local or invalid address – Relay denied”. Meaning, if both your address and the recipient’s are not locally hosted by the server, a relay can be interrupted.
ExceededStorageAllocation“Requested mail actions aborted – Exceeded storage allocation”: simply put, the recipient’s mailbox has exceeded its limits.
MailboxNameNotAllowed“Requested action not taken – Mailbox name invalid”. That is, there’s an incorrect email address into the recipients line.
TransactionFailedThis means that the transaction has failed. It’s a permanent error and the server will not try to send the message again.