Order doesn't complete

Order doesn't complete

Hello.

I am testing my site by making some orders. Unexpectedly when you fulfill the steps of order you see the message below:

Message
The mail function has been temporarily disabled on this site, please try again later.
The mail function has been temporarily disabled on this site, please try again later.

So the order is uncompleted, and I am not receiving any email for the order.
Why is that happening??
Please assist me.

Thank you

Aw: Order doesn't complete

Problem in your server
function mail

Aw: Order doesn't complete

How can I solve it???

Should contact with my hosting agency?

Thank you

Aw: Order doesn't complete

use smtp
or
contact to hosting