When mail are send from Gmail account, they are bouncing. For other domain its working fine. Below is th error.

Delivery to the following recipient failed permanently:

      admin@arvindasingh.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain  arvindasingh.com  by  arvindasingh.com . [198.24.151.123].

The error that the other server returned was:
550-Please turn on SMTP Authentication in your mail client.
550-mail-ua0-f170.google.com  [209.85.217.170]:35908 is not permitted to relay
550 through this server without authentication.

Please help.

Regards,

Arvind Singh