SMTP Error Code: 421 2.3.0

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Lookup for "421 2.3.0"

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 (2.3.0)

Other or undefined mail system status

The destination system exists and normally accepts mail, but something about the system has caused the generation of this DSN.