On the Worldpay plugin configuration panel, I think that the documentation isn't showing up properly. I read ... -- begin paste -- 2. Login into WorldPay Control Panel http://support.worldpay.com/admin/ and set "Callback URL" as follows http://<wpdisplay item=MC_callback> You also have to enable the callback, by checking the following box: "Callback enabled" You should also enable the printout of the receipt, by checking the box: "Use callback response" -- end paste -- I may have aMember confused somehow, but I don't think that explicitly filling in "<wpdisplay" is what I'm supposed to do. Shouldn't it be something link http://mysite.com ? Thanks.
Explicitly filling in http://<wpdisplay item=MC_callback> is definitely what you need to do Try that.