emails not getting sent to customer and admin on order placement.

I have designed custom email template using plugin Email Template Customizer for WooCommerce.. but the mails are not getting triggered not woocommerce actions like new order, cancel order, pay completed, etc.

All mails are working fine with default woocommerce mails and templates, but after activating the above plugin and using it to replace the default templates, the customer and admin does not receive mails on any actions take on website.

can you help me what settings are to be checked or changes to be done so that the mails work fine as expected.