Postfix can send emails but not receive
I'm running a droplet with Ubuntu 14.04 and I've set Postfix, Docevot, and Spamassassin using this guide.
My problem is that I can send emails using Postfix but can't receive them on an email address I've created. What I mean is that I've configured an email address (let's say firstname.lastname@example.org) and added it to my Gmail account (using POP3 to fetch new emails and SMTP to send). If I try to send an email using email@example.com to my gmail account, the email is instantaneously received. If I try to send an email using my gmail account to firstname.lastname@example.org, the email don't arrive or it does but a lot of minutes later.