SMTP Reply Codes
24 verified source-backed entries. Codes are interpreted only inside this namespace.
211System status or help replySystem status or help reply214Help messageHelp message220Service readyService ready221Service closing transmission channelService closing transmission channel250Requested mail action okay, completedRequested mail action okay, completed251User not local; will forwardUser not local; will forward252Cannot verify user, but will accept messageCannot verify user, but will accept message354Start mail input; end with <CRLF>.<CRLF>Start mail input; end with <CRLF>.<CRLF>421Service not available, closing transmission channelService not available, closing transmission channel450Requested mail action not taken: mailbox unavailableRequested mail action not taken: mailbox unavailable451Requested action aborted: local error in processingRequested action aborted: local error in processing452Requested action not taken: insufficient system storageRequested action not taken: insufficient system storage455Server unable to accommodate parametersServer unable to accommodate parameters500Syntax error, command unrecognizedSyntax error, command unrecognized501Syntax error in parameters or argumentsSyntax error in parameters or arguments502Command not implementedCommand not implemented503Bad sequence of commandsBad sequence of commands504Command parameter not implementedCommand parameter not implemented550Requested action not taken: mailbox unavailableRequested action not taken: mailbox unavailable551User not local; try forwarding pathUser not local; try forwarding path552Requested mail action aborted: exceeded storage allocationRequested mail action aborted: exceeded storage allocation553Requested action not taken: mailbox name not allowedRequested action not taken: mailbox name not allowed554Transaction failedTransaction failed555MAIL FROM/RCPT TO parameters not recognized or not implementedMAIL FROM/RCPT TO parameters not recognized or not implemented