[Resolved v1.3.9d/e] Paypal IPN double orders

**parkerlewis** · 2 Nov 2009, 06:22 AM

I am having the same problem.

I have recently had 2 orders come in, exactly the same, but with a different order #.
Only one payment came through, though.

I have had the same thing happen twice in the last week. Both since I turned off Express Checkout. I was having problems with a continuing error with EC where I would get a message saying that the total in the shopping cart does not match the paypal total, or something like that.
I could not find a solution on the forums to that, so just switched off Express Checkout. Now I have had this double order problem twice in a week.

**DrByte** · 2 Nov 2009, 06:54 AM

As stated earlier, blanking out your PDT key has been reported to stop duplicates in some cases.

**DMUK** · 2 Nov 2009, 01:59 PM

I never solved this with standard payments and had to move to Express Checkout, which came with it's own hassles (zen showing orders as paid but never getting the funds - we are still recouping our losses) until I did a clean install which solved the EC problem.

Suggest if possibly you ensure your code is the latest version. I assumed mine was but think that something got screwed up somewhere.

Zen still rules!

**parkerlewis** · 13 Nov 2009, 07:14 AM

Yes I have been saying 'zencart rules' for a while now, but these
paypal issues are really starting to effect my business. I am going to be taking credit cards with my merchant account as of December, which will be a relief.
I am getting so many EC errors (failed checkouts), and now payments standard is doing these weird double orders.
I will keep trying anyway.....hopefully your suggestion works Dr Byte! Thanks as always for your quick replies.

**stardotstar** · 25 Nov 2009, 02:12 AM

I am seeing double orders via paypal.

php 5.2.11
MySQL 5.0.85

ZC:
Zen Cart 1.3.8a
Database Patch Level: 1.3.8

I notice the following on the history of IPN -
most orders show as

"unique"

but the duplicate (order # 58 and 59) has a

"web_accept" first and then the dupe (except for the order ID) is "unique"

I will try blanking the PDT.

Will

**psychosis** · 24 Jan 2010, 05:32 AM

How do you "blank the PDT" ?

this problem just randomly popped up yesterday for me. Its worked no problems just fine for almost 4 years now, through upgrades, etc. and now all the sudden most of my orders are coming through double. Only one paypal payment, but 2 seperate orders, and 2 seperate order numbers. Which wouldnt be a huge deal, but it messes with inventory (so if i have 2 left, it buys both, and removes the product from the website, and even when i delete the duplicate order and restock inventory, it still keeps the item off the website even though it replaces the stock to 1.)

the weird part is it doesnt do it with every order. only about 75%, although from other threads people say it only happens when the customer uses a credit card as opposed to paypal account balance.
i have the latest zen cart version and all that. like i said, this was working just fine until yesterday.

this is very frustrating, and i would love to know if anyone has had any luck with fixing this, or even diagnosing what the problem actually is.

**psychosis** · 2 Feb 2010, 01:53 AM

bump just in case anyone has found anything about this?

**DrByte** · 2 Feb 2010, 04:43 AM

Originally Posted by psychosis

How do you "blank the PDT" ?

Simple:
1. Login to your admin
2. Take your mouse and click on "Modules"
3. Slide your mouse down to "Payment", and click.
4. Slide your mouse down to the "PayPal IPN" module, and click.
5. Click the Edit button.
6. Click in the PDT field, and delete what you had previously put in there.
7. Scroll down the screen until the Save button appears.
8. Take your mouse and slide it to the Save button and click.

**redheads** · 5 Feb 2010, 05:50 AM

Quick Qs since I have had several of these double order problems lately...

If you blank the PDT how is the payment record updated - I thought that value helps feed the data back to the cart and was necessary. I obviously misunderstand. Can you clarify what that value does, why blanking it is is ok, will it affect any other function of our reports, etc?

Thanks for any light you can shed. I do not need a LOT of detail, just wondering how it might affect my reports when next year's tax time rolls around, or if I will no longer see the transaction details, or... ??

:-)

**DrByte** · 5 Feb 2010, 08:06 AM

"Website Payments Standard" is PayPal's least-sophisticated method of handling transactions. In order for it to work with a shopping cart, your store must send the order amount and customer details to PayPal along with a request to have the customer log in and authorize the payment. Then for your store to know about the transaction it must wait for PayPal's servers to talk to *your* server in the background. Many times that communication fails for a multitude of possible reasons. PDT is a bandage PayPal added to allow the store to request the details of the transaction to confirm it before the background notification happens. It too can fail for many reasons. If you blank out the PDT value, then Zen Cart won't bother attempting to use PDT to check on order details, thus forcing you to rely on the background notification referred to as IPN.

The best way to avoid all those problems is to click "Remove" on the Website Payments Standard/IPN module, and use Express Checkout instead. It's a much more mature technology and not subject to the many weaknesses of the IPN/PDT approach.