Order Confirmation Email

I'm using Opencart Version 2.1.0.1

I'm receiving all the emails except for order confirmation email.

The admin and the customer are not receiving the order confirmation email. Other than this all other services which require email are working. I'm using zohomail in smtp.

I want the client and the admin to receive the confirmation email soon as the client's order's a product.

Anyone know how to solve this ?