I'm integrating paypal website payment pro (US)in my shopping cart Magento. I have got API username,api pwd,api signature from paypal. I have tested by creating a form from the ref site https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/library_download_sdks#NVP It works well and im able to login to the sandbox and see the transactions But it does not work with Magento 1.4.2 Could any body let me know the soln ?