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SMTP Response Codes

The SMTP response codes and their meanings are shown in the following table.


Prior to versions 3.1 and, Momentum would not respond correctly to a 251 (User not local; Will be forwarded) response from a remote server. It put the message in the delayed queue.

211System status, or system help reply
214Help message service ready service closing transmission channel
250Requested mail action okay, completed
251User not local; will forward to forward-path
354Start mail input; end with . service not available, closing transmission channel
450Requested mail action not taken: mailbox unavailable
451Requested action aborted: error in processing
452Requested action not taken: insufficient system storage
500Syntax error, command unrecognized
501Syntax error in parameters or arguments
502Command not implemented
503Bad sequence of commands
504Command parameter not implemented
550Requested action not taken: mailbox unavailable
551User not local; please try
552Requested mail action aborted: exceeded storage allocation
553Requested action not taken: mailbox name not allowed
554Transaction failed
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