Problem with order payed through Paypal

I've been working on setting up PayPal's Website Payment Standard with my ZenCart install at http://joyasenplata.com.mx/index.php and still haven't had a successful checkout.

The thing is I checkout using PayPal for payment, I proceed and get taken to PayPal where I fill out the payment info and am returned to the store. Here's where the problem is obvious.

The order doesn't show in the account history of the customer's account, or the order's history in the admin side. It is also removed from the cart as if it were complete.

PayPal does process the payment alright, but the store has no record of such order anywhere to be found.

What can I do to fix this? I've been trying for days already, not wanting to bother here until I didn't know what else to do.

Thanks in advance!

Here is a collection of tips for troubleshooting the communications problems between PayPal's server and your server:
http://www.zen-cart.com/wiki/index.php/PayPal

Thanks for your reply. I had already found that article and followed the instructions without success.

The one thing I didn't know how to check that there was no IP block or firewall preventing PayPal from talking with the server, but I tried the tool IPN Check I found in the extras folder, which I moved to the store's root dir (ipncheck.php), and it said there was no problem, so I understand they're talking.

Now, one thing that seemed a bit off, but it may not really be a problem, is in the checkout_confirmation page, the PayPal form has the following line:

<input type="hidden" name="notify_url" value="http://joyasenplata.com.mx/index.php?main_page=ipn_main_handler.php" />

Is it correct?

The odd thing is that PayPal gets all the data and makes the charge and the emails are sent by PayPal to the parties, but the store keeps no record. It doesn't even have the order in pending status, it has nothing, nowhere. So, even if the store owner gets the PayPal email and find out he got a new order by it, he can't know what was in the order.

Could you tell me what else could be the problem or if you need any other data to get closer to it?

Well, I think I hit the nail on the head, cause I tried that odd URL to the ipn_main_handler.php file and it didn't work as the direct URL to the file did. So I copied the source code of the checkout_confirmation page, edited the URL in my text editor, hit preview and clicked on the checkout button. I got sen to PayPal, I paid and got sent back to the store. This time the order was there in my customer account history and the admin side had notice of it too.

I'll go look into the payment module to fix the code that generates that line, now. I had not touched it, it's what came with my ZC 1.3.8a.

Found the issue. It was the zen_href_link function that was modified by ZenMagick. I'll bring up the issue with ZM's developer in his forum. Sorry for the trouble and thank you for your help!

Thank you for letting us know the problem is not in the Zen Cart core code.