An error has occurred while processing coupon code. See console log for more details

Hello,

In Joomla ‎4.4.14 and VirtueMart 4.6.4 with PHP 8.3.30 I have a problem with coupons.

Specifically, I have created a coupon with a 10% discount, I have set the dates correctly, it is published and when I go to apply it to my cart it displays the following message:

Invalid Token, in view=cart task=updatecart

An error has occurred while processing coupon code. See console log for more details.

The coupon is named BeYourValentine.

You can try applying it to the following link: https://athanasios.jewelry/index.php?option=com_virtuemart&view=cart&task=vmsendcart&v=2&data=Lcg7DoAgEAXAu7x6C0QNulcxxBCkoFAUsDCEu_uJ5UxBdMnl2ZqYwYJ-Hvn6ZMO5h222YXFggOCzWxN4KvBgOSpJMOACJZ7UhEGCGyX6jtC-U6uuNw

Could you help us?

Thank you for your prompt response,

I am using the latest version of vp one page checkout.

Because I do not have the necessary knowledge to find a solution, related to the non-functioning of the Token. I tried to get help before answering you, from AI.

I quote below the tests I performed, in case they help to find a solution. I hope you can help me. Thank you.

Troubleshooting steps already taken:

1. Session Configuration:

   • Switched Session Handler from "Database" to "Filesystem".

   • Set Shared Sessions to "No".

   • Disabled Track Session.

   • Verified Session Lifetime is set to 60 minutes.

2. Environment Settings:

   • Error Reporting set to "None" (to prevent PHP 8.3 notices from breaking JSON responses).

   • Verified Cookie Domain/Path are empty and Force HTTPS is enabled for the entire site.

3. Code & Template Checks:

   • Tested with both the VP One Page Checkout and the Default VirtueMart Cart layout. The issue persists in both.

   • Modified default_coupon.php to manually include

     <?php
 echo JHtml::_('form.token'); 
?>
     .

   • Cleared Joomla and Browser cache multiple times.

4. Network/Console Analysis:

   • Browser Console: Returns SyntaxError: JSON.parse: unexpected character because the server returns a full HTML page (Redirect 303) instead of JSON.

   • Network Payload: Confirmed that during the task=setcoupon POST request, the Joomla Security Token is missing from the request headers/payload, even when the token is present in the HTML form.