I am trying to send email to my zoho account, to my custom domain (not zoho.com) from another email account gmail.com

Every mail i send i get the following error:

Final-Recipient: rfc822; admin@mzayka.com.ua
Action: failed
Status: 5.0.0
Remote-MTA: dns; mx.zoho.eu. (31.186.226.32, the server for the domain mzayka.com.ua.)
Diagnostic-Code: smtp; 553 Relaying disallowed
Last-Attempt-Date: Wed, 07 Jun 2017 03:41:36 -0700 (PDT)

What can i do?