'Fail because the server sent a malformed authentication challenge.
@param code: The server status code from the most recently received
server message.
@type code: L{int}
@param resp: The server status response from the most recently received
server message.
@type resp: L{bytes}'

def esmtpAUTHMalformedChallenge(self, code=(-1), resp=None):

    self.sendError(AuthenticationError(501, 'Login    failed    because    the    SMTP    Server    returned    a    malformed    Authentication    Challenge', self.log.str()))
