First of all i am not a sender, Sender is our client (example.com & they are using google apps mail server) &
i am a recipient (testdomain.com & use Exim mail server )
when
123@example.com sends mail to
123@testdomain.com it doesn't delivered
It means our recipient server (testdomain.com & use Exim mail server ) is blocking email
I found error below while checking exim logs
2011-01-03 15:14:08 H=(EXPDSI01) [209.143.xx.xx] rejected MAIL <123@exp-inc.com>: Access denied - Invalid HELO name (See RFC2821 4.1.1.1)
But when
123@example.com sends mail to any other email service provider like yahoo, google,hotmail,rediffmail,aol it successfully delivered
means our Exim email server blocking email with error Access denied - Invalid HELO name (See RFC2821 4.1.1.1)