Signup for a free Mailgun account
The next step is to get setup with a free Mailgun account. What is Mailgun? From the Mailgun website:
"Mailgun is a set of powerful APIs that allow you to send, receive and track email effortlessly.
Think of Postfix as the mailbox at your house - when you want to send a letter (email) to someone else, you put it in the mailbox (Postfix). Then the mail is picked up by the mail carrier (Mailgun) and delivered.
Mailgun is optional - you can send and receive email directly using Postfix, however I would highly
recommend using Mailgun as your delivery service, as they will get your email delivered to a higher percentage of your customers than delivering on your own.
The first 10,000 emails each month via Mailgun are free - after that it is just 50 cents for every 1,000. You can signup for an account here:
Once signed up, go to your Mailgun Control Panel:
and click on the "domains" tab then the big "Add Domain" button: