Tbay Cena store checkout issue when payment gateway enabled

I had a purchased tbay Cena store theme but my support expired. My store is working fine for cart and checkout pages. But when I enabled the payment gateway plugin the website stop showing checkout and cart pages and website keep on loading. I had tried wordpress default theme and WooCommerce plugin they are working fine with all other plugins including payment gateway plugin. The initial issue was “force secure checkout for WooCommerce” which I had fixed in options.php page from no to yes. But the problem in not fixed yet. Please some one help me out to fix this checkout page issue with Cena store theme.
Thank you in advance.

Here is my store link. shop.glistensecurity.com

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