Thank you very much for your reply. The problem is that the account is activated for sending and receiving emails. I receive all e-mails sent to that account by people except the emails which is sent through the script on the website. Script is working fine as i wrote in my first post. Because the scripts sends to three different email addresses. The other two arrive without any problem, even the one which is a gmail email address. But the third...
I underestand that this is a Beta release before joining the program. But honestly I never thought of not receiving order confirmations!
I hope somebody who works in Gmail for domain team try to help me and solve this problem.
Thank you again for your reply.