Paypal Standard Checkout FAIL

I followed the instructions to the letter as how to setup the paypal payment method within CS Cart. I did one test and it seemed to work. However, the last week when you place an order, when you click to go to paypal to finalize the payment you get this message:

This invoice has already been paid. For more information, please contact the merchant.

And the order shows up as “incomplete” in the Administration.

Please help in any way you can!

If you are trying to do this on the same test invoice then this is what you will get. Try creating another test order and try again.

I know that I did not try that test before. Someone else did though. So, if I order something and someone else orders the same thing, does Pay pal think it’s a duplicate?

No PayPal assigns unique TXN numbers for each order

Huh. I guess what I’m saying is. Earlier in the week. The woman who owns the cart did a test transaction for $1.00. Then later when she got an e-mail from someone saying that the cart wasn’t working, she tried another transaction for $1.00 and got the error above.

Then I, since I’m helping her, tried the same type of purchase on my computer with different username/password and everything and I got the error. I hadn’t tried before, it was my first time.

This time I attempted a $16 order and it went to PP just fine. I would like to see her do a complete order, and then I try that same order and see if I get the error.