I have a custom made mailing application that use 2 servers, one called master and the second small. in the small server we have powermta installed, when i try to send emails from the mailing application we dont see the active connection IN, and OUT. however when i press another button that sends what we call a Test mail it does work. If you succeed debugging and fixing this connectivity and sending issue, i ll outsource from you many more features.
You must debug and fix as soon as possible