Mail script problem

[alessandro]

Hello to all last work I hope! In practice, the problem is this:

1 - I have a domain registered with the mail server to another supported

2 - The email sent from external mail arrives safely

3 - If using a script based on pinco.com I try to send a mail to test@pinco.com and the mail server itself gestista arrives without problems.

3 - If using a script based on pincopalla.com I try to send an email to test@pincopalla.com not get the mail "your mail server is external"! Any ideas??

Reading the logs I find this practice in check:

/ etc / postfix / ispcp / mailboxes

but not finding the mail and deletes it spammmm classifies as cool as you can solve this problem???