SMTP Error Code: 421 5.0.0

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Lookup for "421 5.0.0"

Permanent Error - This status code indicates a permanent issue and is unlikely to resolve itself. You should contact the Email Service Provider.

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 (5.0.0)

Other undefined Status

Other undefined status is the only undefined error code. It should be used for all errors for which only the class of the error is known.