Help! My Opencart 2 site can't send invoice & order emails

Can someone help me resolve this asap?

I installed Opencart 2.0.1.1 on website
It does not send order invoice to the customers when a customer orders nor does it send order email to the web admin.
Contact form too doesn't send to admin email.
I am stuck and don't know how else to resolve this.
This is unlike the Opencart 1.5 which sends order emails to admin and customer.

Try google for "your hosting provider" + "smtp configuration"
I've done that way with hostmonster.