Help request: domain not resolved

Help request: domain not resolved

Hello!

We are experimenting some problems with the e-mail address. Specifically, we cannot send nor receive mails. Any time I try to send one e-mail, I get this message. Could you please help me? 

 ----- The following addresses had fatal errors -----    
   [Status: DOMAIN_NOT_RESOLVED, Address: <alfredo.sucre@synacapital.com>, DOMAIN_NOT_RESOLVED]

Message will be retried for 4 more day(s)

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

 Received:from mail.zoho.com by mx.zohomail.com
	with SMTP id 1488823824256993.3933665268061; Mon, 6 Mar 2017 10:10:24 -0800 (PST)
 Message-ID:<ab1f05f7-2a92-4f6e-9e6e-cdb1536a9ef3@email.android.com>
 Date:Mon, 06 Mar 2017 19:10:23 +0100
 From:Joaquin Pardo Diaz <joaquin.pardo@synacapital.com>
 User-Agent:Zoho Mail
 To:alfredosucre <alfredo.sucre@synacapital.com>
 Subject:Prueba
 Content-Type:text/html; charset=utf-8