When my form redirects to paypal sandbox page with my all shopping details.Paypal asks me to login or fill the form.I have login details for paypal and when I enter the proper username and pass it gives me error says "Please make sure you enter your email address and password correctly".I know they are correct.
PayPal has a Developer Forum dedicated to Sandbox accounts that would be able to assist you better than I am able to here is the direct link to the Sandbox Forum. I hope this helps.
Misty
