Unable to Add Products to Cart
Clicking Order Now on the shopping cart product selection page (
cart.php) or following a direct product order link (for example,
http://example.com/whmcs/store/1) appears to refresh the page and shows the product selection page again.
When this happens, the ordering process may not proceed to the product configuration or view cart stage.
This issue may be due to an invalid URL (missing the slug) in the product group's configuration.
To resolve this:
1. In the WHMCS Admin Area, go to Configuration > System Settings > Products/Services.
2. Edit a product group.
3. Enter the desired product group URL (slug) in URL.
4. Click Save Changes
5. Repeat the process for every product group.