Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit

Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit

My email id is ekansh@menias.com and whenever I'm sending the email to someone, I'm receiving the error message as:  Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit.

Please resolve this to the account ekansh@menias.com

Thanks in advance!

Ekansh