title: Magento 2 Apply discount code is not working on checkout page
body: <p><img src="https://i.stack.imgur.com/Qdi0m.png" alt="enter image description here">
  I am facing issue when apply discount code on magento 2 checkout page.
  On Cart Page Apply discount code is working fine but it is not working on checkout Page.</p>
  
  <p>404 Bad Request</p>
  
  <p><img src="https://i.stack.imgur.com/lwypl.png" alt="enter image description here"></p>