ERROR 554 5.1.8 Sender Address Blocked code(554)

ERROR 554 5.1.8 Sender Address Blocked code(554)

We have an email with Zoho ( comercial@bruiser.com.br), but, when we try associate the account in GMAIL, the server shows this message: 
554 5.1.8 Sender Address Blocked code(554)

I see this error appear when the limits of returns exceded 10 messages, and Zoho blocked the account. What i do for disblock the account?