I am using Magento 18.104.22.168 on my Ubuntu localhost. I installed ssmtp to send email. I tried subscribe letter on my website and receive confirmation email, so it worked.
However, when I checkout a product. It didn't send any email to customer's email address.
I opened var/log/mail.log. All subscription confirmation mails are here, but there isn't any checkout mail.
I guess the problem is between Magento and SSMTP..
Please help. I don't understand why...