INVALID_ADDRESS, ERROR_CODE :554, ERROR_CODE :5.7.1 <sender-of-o51.zoho.com[135.84.80.216]>: Client host rejected: Access denied

INVALID_ADDRESS, ERROR_CODE :554, ERROR_CODE :5.7.1 <sender-of-o51.zoho.com[135.84.80.216]>: Client host rejected: Access denied

Help please
The problem is we can not to send email to some addresses, because  we receive the message:

INVALID_ADDRESS, ERROR_CODE :554, ERROR_CODE :5.7.1 <sender-of-o51.zoho.com[135.84.80.216]>: Client host rejected: Access denied

Thanks.

Claudio