Help - "do not have SMTP Authentication turned on in your 550 email client"

[andy1970]

"javax.mail.SendFailedException: Sending failed; nested exception is: javax.mail.SendFailedException: Invalid Addresses; nested exception is: javax.mail.SendFailedException: 550-(guru.usedvehicles.in) [209.97.207.204] is currently not permitted to relay 550-through this server. Perhaps you have not logged into the pop/imap server 550-in the last 30 minutes or do not have SMTP Authentication turned on in your 550 email client."

I am facing this problem while sending any emails (non usedvehicles.in) from java application. I did confirm that etc/localdomain has the listing of domain. I also varified in WHM for propersetting. What else could be causing problem ? Can anyone help ? You can charge for the effort.