I and read many post but don't find the similar thread.

I used the sandbox to test the shop payment.

Every thing is normal but when it go to paypal page,
The shopping cart's product don't show at paypal page.
and when pay the bill, it don't show the merchant name(email account)
automatically.

I don't know where is the wrong setting i made.
I just follow step by step as the link following
osCommerce module: PayPal Website Payments Standard-SOFTWARE REFERENCE LIBRARY/OSC Community Contributions

But don't know which part i set wrong.

Do anyone can help me?