Cart page Error message: "There was an error while updating your cart..."

Store: https://jnslabs.com

The message “There was an error while updating your cart. Please try again.” appears whenever a customer tries to change the quantity of an item in their cart.

I have reverted the cart-template.liquid file back to it’s original version, but the problem persists.

Can anyone help me with this?

Video grab of the error: https://www.awesomescreenshot.com/video/1592714?key=392026bbf296404c8094fc746b8520ea

Hi,
Actually items are updating and then still shows error
in theme.js, when it fails to fetch that’s why showing error

Thanks. But how do I fix the issue? I have no knowledge of Javascript.

it require to find exact issue, I’m not sure why its happening

but just temporary solution is to comment that line