Delivery to the following recipient failed permanently:

    *** Email address is removed for privacy ***

Technical details of permanent failure: 

Google tried to deliver your message, but it was rejected by the server for the recipient domain avangate.co.kr by 41dd7b2dbdc7458b19fa3cc6b4de3e.pamx1.hotmail.com. [65.54.188.109].

The error that the other server returned was:

550 Requested action not taken: mailbox unavailable

====

i complete my domain MX records setting.

why i got that message?