On 28 Aug 2019, at 22:50, Eliza wrote:
Hello,
on 2019/8/29 10:42, Andrew Bernard wrote:
421 Temporary System Problem. Try again later.
421 Try again later, closing connection.
421 Server busy, try again later.
The SMTP error 421 is normally used for temporary problems on the
mail server or a problem with the recipients email account.
Some mail providers might also return 421 after you reached a limit
(restriction) on your mail account (see SMTP Error 451 below).
But I know some antispam systems get abused to return 4xx even there
is neither temporary system problem nor server busy. They just doubt
this is suspicious message and return 4xx codes.
Which is their absolute right to do for whatever reason they see fit. It
is NOT "abuse" in any sense.
Andrew didn't mention the enhanced status codes of RFC3463, which
include the '4.7.0' you are seeing in error messages. That is a generic,
intentionally vague, and perfectly valid status code.
--
Bill Cole
b...@scconsult.com or billc...@apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
