SMTP Error Code: 421 2.6.0

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Lookup for "421 2.6.0"

This status code indicates a successful delivery or other operation. Any details are simply notes.

Basic Status Code Details (421)

Service not available, closing transmission channel [This may be a reply to any command if the service knows it must shut down]

Enhanced Status Code Details (2.6.0)

Other or undefined media error

Something about the content of a message caused it to be considered undeliverable and the problem cannot be well expressed with any of the other provided detail codes.