Inbound mail issues

Inbound mail issues

Here is the logs of the postmaster:

Gmail:
Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain h****host.com.br by mx.zoho.com. [165.254.168.50].

The error that the other server returned was:
554 5.2.3 MailPolicy violation Error delivering to mailboxes


Hotmail:
This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

       contato@h****host.com.br
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What's going on?