After installing iRedmail 0.8.4, I have checked receiving emails from other domain. I sent an email from my gmail account to the postmaster account. It is getting received in postmaster after 15-20 minutes. Why there is a delay ? I use POP in Thunderbird to receive emails send to postmaster. I am sure there is no problem in the Thunderbird side, as the receiving works fine for my other email accounts (gmail).
Thanks.