Ty

I am having the exact same issue and can’t seem to solve it.
I also am having the login issue and not a firewall issue.
There is no button for “ADD PARAM TO FIREWALL ALLOWLIST”

Zapier/ WooCommerce suggest to whitelist the api endpoints.
I just don’t know how to add them under Allowlisted URLs.

Note: That whitelisting the IP won’t work as the IPs will change and vary since Zapier is hosted on AWS and use different servers/ IPs can easily change in the future.

Link for API Endpoints:
https://docs.om4.io/woocommerce-zapier/developer-documentation/#api-endpoints

After a little bit of scanning and searching the plugin files… I figured it out.
I think this is correct. It works for me.

This will change it on all WooCommerce pages too..
Use a child theme functions.php

add_filter( 'woocommerce_product_single_add_to_cart_text', 'ql_replace_add_to_cart_button_text' );
add_filter( 'woocommerce_product_add_to_cart_text', 'ql_replace_add_to_cart_button_text' );
add_filter( 'mkl_pc/add_to_cart_button/default_label', 'ql_replace_add_to_cart_button_text' );
//Replace Add to Cart text with Buy Now! 
function ql_replace_add_to_cart_button_text() {
 return __( 'Purchase', 'woocommerce' );
}