Double-Order, One Charge (a bug in the PayPal IPN - Website Payments Standard?)

[ilikemike]

What does it take to switch to PayPal Express?

In the Zen-Cart Admin console you just need to enable PayPal Express and enter the codes provided by PayPal. It's really simple, no coding required or add-on install. It took me less than 5 minutes.

Do I have to change anything with my PayPal account?

There is nothing to change in your PayPal account -- if you already have a Business Verified account with PayPal. All you have to do is get the API Access codes from PayPal:

http://www.zen-cart.com/index.php?main_page=page&id=15

Hope this helps.

[Tech-E]

Thanks.

Are you guys absolutely sure that PayPal Express allows a customer to use a credit card without setting up a PayPal account? I have not been able to verify that on the PayPal site and when I submitted the question to PayPal, I got an ambiguous response that did not answer my question.

With Express Checkout, your customers don't have to re-enter information
already stored on their PayPal account. After approving use of PayPal,
your customers return to your site to complete and finalize their
purchase. This provides your customers a secure and convenient payment
flow.

This looks like a canned response.

About 60% of my customers who use PayPal do not set up an account. I can't use Express if a customer needs to sign up for a PayPal account.

[DrByte]

Are you guys absolutely sure that PayPal Express allows a customer to use a credit card without setting up a PayPal account?

If you enable "pay without account" in your Paypal account's payment-receiving preferences, then yes.
ref: http://tutorials.zen-cart.com/index.php?article=28

[ilikemike]

What does it take to switch to PayPal Express?

Did you eventually switch to PayPal Express?

Did it solve the problem?

I actually tried switching to PayPal Express but that created a different problem with my download-only products, so I switched back until I find the time to do a total migration from 1.3.8a to 1.5.0, removing a few unused add-ons in the process.

As a result, I am still experiencing this problem every once in a while. I am not sure whether this is in core-ZenCart or one of the add-ons the induces this problem.

BTW, the following old thread looks like it is referring to the same problem, and indeed the product in my case appears in two different categories via linking. Perhaps that's a clue to the root cause of the problem? http://www.zen-cart.com/forum/showthread.php?t=68306

[RixStix]

This just happened to us overnight.

Customer placed order. All appears fine.
PayPal generated a second order (7 seconds later) with no customer data. Order total $0.00. Payment method GV/DC. Looking at order details, the amount embedded was identical to the total of the customer placed order.

IP address was PayPal. host address was notify@paypal.com

Using PayPal Express.
Zencart v1.3.9H

The only difference that I can see is that the customer chose a different currency than default. AUD vs USD.

[DrByte]

Was it Express Checkout? or Direct-Payment (website payments pro)?

[ilikemike]

Using PayPal Express.
Zencart v1.3.9H

I am happy that I didn't waste time upgrading to 1.3.9h* only to switch to PayPal Express and find out that it didn't really help.

My modest experience taught me that if no one can come with an explanation for the root cause of a problem (however rare & random it is), then it will show up again, even in a newer & more robust version.

In this post there is a hint about "a server lag problem". But how can we take it from here? Is there a way to simulate some condition that can consistently re-produce the problem, so that an accurate diagnosis can be made and a solid fix can be tested?

*To clarify, upgrading to 1.3.9h is highly recommended, but not only to fix this particular problem.

[RixStix]

It was Express.

We use Auth.net instead of WPP for CC transactions.

[RixStix]

FWIW

PP order id is identical for the 2 sequential zencart orders.

First created by the customer. 2nd created by PP.

[DrByte]

A DRASTIC workaround would be to go into your PayPal account and turn OFF the Instant Payment Notifications checkbox, so that it doesn't tell your store about ANY changes to your transactions, nor notifications of new transactions. This means your store won't be alerted of any echeck clearing or refunds or releases of holds, etc. You would have to update the order status by hand in those cases after you receive the email from PayPal about the event. If you can live with those consequences then that would be a workable "fix" for you.