I guess I'll dip my toes in here and admit that I can't figure this out.

Synopsis:  I've setup Postfix to be a mail out only smtp server. I just want it for our Joomla based web pages and our helpdesk to be able to mail to users from the local server. The problem is this: I can mail to any domain (gmail, hotmail, yahoo, etc) without problem, but I can't receive mail directly through our A-plus based mail (the worst!). What happens is that A-plus' server rejects the user as unkown even though I know it is correct. What really gets my goat is that after that message is returned to my server it is then delivered to the A-plus server and thusly shows up in my webmail and email client. Below are my configs.