SMTP Error Code: 421 2.7.9

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Lookup for "421 2.7.9"

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 (2.7.9)

Authentication mechanism is too weak

The selected authentication mechanism is weaker than the server policy permits. Client should retry with a new authentication mechanism.