Spam filter · 4.x.x transient failure
Every SMTP 450 response on record from Email Security.cloud, with the verbatim text, the enhanced status code, a severity rating and a plain-English fix.
The requested action did not happen because the mailbox was briefly unavailable, for example locked, busy, or lightly rate limited. The sending server keeps the message queued and retries it.
smtp;450 Requested action aborted [9] #-#, please visit https://knowledge.broadcom.com/external/article?legacyId=TECH246726 for more details about this error message.
The receiver deferred this message and will retry it automatically. A failure that sticks around usually traces back to rate limits, reputation, or a policy on the receiving side.
The requested action did not happen because the mailbox was briefly unavailable, for example locked, busy, or lightly rate limited. The sending server keeps the message queued and retries it. At Email Security.cloud, it is a temporary deferral that is retried automatically, and the specific reason is in the enhanced status code and message text of each response below.
Match your bounce text to one of the responses below and follow its guidance. Recipient-side wording means fix the address. Authentication or reputation wording (SPF, DKIM, DMARC, blocklist) means fix your sending setup, and check Email Security.cloud's postmaster documentation.
