Originally Posted by sygram
why not share the solution ?
We might need it someday as well
Thanks for taking interest.
I am more than happy to do that, it was nothing to do with ISPConfig or any other configuration related to postfix, the culprit was ASSP it was blocking (postmaster & abuse)emails to that particular domain, Hence in ASSP you need to list the domain in the local doamins file & you have to do that everytime you add a new domain to CP.
Hope that helps