I have a domain set up through GoDaddy. I set up a cpanel e-mail forward for email@example.com to my gmail account.
Test e-mails sent to firstname.lastname@example.org get bounced back with a "Recipient address rejected: Access denied" error. If I log into webmail through cpanel, I can send e-mails to the gmail address with no problems.
I have tried using a corporate e-mail account (not @Gmail.com) to send the message, same problem. It gets bounced back with the same error. What is going on?