Email Rejected to @antamina.com domain, Please Help

Email Rejected to @antamina.com domain, Please Help

We are sending email to domain @antamina.com and receive this message. the problem happened since yesterday.



-----Mensaje original-----
De:  mailer-daemon@mail.zoho.com  [mailto: mailer-daemon@mail.zoho.com ]
Enviado el: martes, 19 de mayo de 2015 12:56 p.m.
Para:  felipe.castaneda@gruassanjose.com
Asunto: Mail Delivery Status Notification (Delay)

This message was created automatically by mail delivery system.

THIS IS A WARNING MESSAGE ONLY.

YOU DO NOT NEED TO RESEND YOUR MESSAGE.

The original message was received at Tue, 19 May 2015 10:56:17 -0700  from felipe.castaneda@gruassanjose.com  [ felipe.castaneda@gruassanjose.com ]

    ----- The following addresses had fatal errors -----
   [Status: Error, Address: < jdolores@antamina.com >, ResponseCode 421,  Returning empty domain in greet for host  smtp.antamina.com ., Status: Error, Address: < jvillarreal@antamina.com >, ResponseCode 421,  Returning empty domain in greet for host  smtp.antamina.com .]

Message will be retried for 4 more day(s)

    ----- Transcript of session follows -----

 Received:from ideaPC (190.239.85.147 [190.239.85.147]) by mx.zohomail.com
        with SMTPS id 1432054351397262. 2216540852784; Tue, 19 May 2015 09:52:31 -0700 (PDT)  Message-ID:<000001d09254$ 2270cb70$67526250$@ gruassanjose.com >
 Date:Tue, 19 May 2015 11:51:57 -0500
 From:Castañeda, Felipe < felipe.castaneda@gruassanjose.com >
 To:< jvillarreal@antamina.com >
 Cc:< jdolores@antamina.com >
 Subject:ACTIVACION COMBUSTIBLE
 Content-Type:multipart/mixed;
        boundary="----=_NextPart_000_ 0001_01D0922A.399D3470"