Verify Sender?

[teck]

I\'m attempting to email an account on my cpanel box from another box using a php script but get the following error in my logs when doing so:

stat=Deferred: 451 rejected: temporarily unable to verify sender address (try again later)

Is there a configuration I have to change or something so this will work?

[Curious Too]

In your Exim config file change \"sender_verify = true\" to sender_try_verify = true. The software will still try to verify the sender but not reject the email message if it can\'t.