This is what I've done so far
- I've already configured the store's sales email to the correct email addresses - Test smtp (send test email)
My mailgun configuration works properly. Email were being fired when a user subscribe, etc.
It seems that this problem occurs when a new order is placed.
Because when I view sales>orders and then view a certain order and click "send email" the email is being sent.
Can anyone help me debug this problem.