my store can not send mail after payment

[smithveg]

Hello,

 

I've try a demo purchase in my store. It can go through the payment gateway and back to my store when success. But as a customer, he can not receive the order success e-mail from my store. And as a store owner, i also can not receive any order notification. I'm not sure why... The only mail i can see it from payment gateway send to customer "your order detail".

 

I hope my problems and explanation is make sense. And hopes someone can helps me...

Thanks.