In some cases, the buyer may encounter an HTTP 404 or 414 error page when returning to the merchant site.
To avoid this error, you must change the return method used so that the data sent to the return URL is received via a requestPOSTrather than in the URL as key-value pairs (query string).
If you're using a payment module:
- Go to the module's settings.
- Look for the “Return to store” section.
- Set the value of the “Return method” parameter toPOST.
You have implemented the Redirect Form API:
In your payment form, populate the fieldvads_return_modetoPOST.