Discount input not working on Shopify cart page

[khalildanish]

I need a coupon code input on my cart page but it doesn't seem to work in its plain form:

<input type="hidden" name="discount" value="{{ settings.modal_promo_code }}" >

I have it right before the submit button, inside the form. Live coupons are not being applied to the order on the checkout page. Is there anything else I need to do for it to work? Edit: The form looks like this —

And it redirects to a URL like this:

<form action="/cart" method="post" class="cart">
         <input type="hidden" name="discount" value="{{ settings.modal_promo_code }}" >

https://store.com/4934605xxxx/checkouts/04d6478feeb9d3262fbea5571b682ebc?_ga=2.260083023.358228188.1... it seems there is a conflict that doesn't let the discount apply to the URL or get removed by ?_ga=2.260083023.358228188.1608464294-110675315.1604953057 because when disabling the JS in the chrome setting and submitting the checkout again it works and the discount is getting applied. any thoughts on this? how can I get this working like this: https://store.com/4934605xxxx/checkouts/04d6478feeb9d3262fbea5571b682ebc?_ga=2.260083023.358228188.1...

thank you