SMTP Error Code: 550 4.5.4

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Lookup for "550 4.5.4"

Temporary Error - This status code indicates a transient issue and may resolve itself.

Basic Status Code Details (550)

Requested action not taken: mailbox unavailable [E.g., mailbox not found, no access]

Enhanced Status Code Details (4.5.4)

Invalid command arguments

A valid mail transaction protocol command was issued with invalid arguments, either because the arguments were out of range or represented unrecognized features. This is useful only as a permanent error.