Cannot send request using Zoho as a service

Cannot send request using Zoho as a service

So we have a website and after user registers , we want to send an email.
But it seems like Zoho service is not allowing us to send mail, and giving an error :
 { Error Message failed : 553 Relaying disallowed error as noreply@hydra,com },
 instead of having correct email address and password.