Configuring ZenCart and PayPal Error 10413 solved

Configuring ZenCart and PayPal Error 10413 solved

Now that PayPal is coming to South Africa, I figured that I�d upgrade my ZenCart site to connect to PayPal�s express checkout. 
I enabled ZenCart�s �PayPal Express Checkout� payment module and started configuring the parameters.
Oops, I needed to enter some API credentials � so I followed the instructions on how to get those.
I upgraded my PayPal account to �Premier� level so that I could accept payments and get an �API username� and �API Password� and �Signature�, and pointed it to �Sandbox� mode.
Sandbox mode? � yup, mmm� that should have got me thinking � but it didn�t. 

I then (naively) tried to process a transaction from my ZenCart using my real PayPal logins and got the following error �10002 Security error - Security header is not valid�.  That gave me further clues that I couldn�t use my real PayPal logins and API settings and use the �Sandbox� mode.  I needed to create new dummy accounts and logins and APIs on the sandbox.PayPal server.

So, I registered as a developer on the https://developer.paypal.com/ site and downloaded the �PayPal_Sandbox_UserGuide� and a few clicks later I was creating the sandbox parameters and users that I could use to test my shopping cart.  I created a few users with different accounts, in different parts of the world, with lots of money so that they could purchase to their hearts� content.



Then I got to the difficult part. I thought that it would be easy to go from the shopping cart to PayPal and process the payments � BUT, it wasn�t � sometimes the purchases went through fine � others it didn�t.  I didn�t realise that the small transactions worked fine � but not the ones over R1,000.  I kept on getting the error �10413 Transaction refused because of an invalid argument. See additional error messages for details. - The totals of the cart item amounts do not match order amounts.�  I Goggle�d a bit � but nothing really helped, until I found this posting by Levi Senft: �ZenCart and PayPal: 10413 Transaction refused because of an invalid argument. Solved!�.  The posting explains how the comma separator is the cause of the problems, as well as a fix.

I modified the paypalwpp.php file as directed and voila � it was solved.  No more error 10413 (that was really starting to haunt me!)

I�m looking forward to many transactions facilitated by PayPal in South Africa.

Update 07April2010:
I�m not sure why, but I started getting the 10413 error again.  Perhaps I didn�t test the above solution thoroughly enough.  I Google�d some more and found this solution by �gmail�: http://www.zen-cart.com/forum/showpost.php?p=675592&postcount=62:
That seemed to work first time � but beware it�s not thoroughly tested.  You can download the modified paypalwpp.php file to save you some typing:  It INcludes both fixes described above  paypalwpp.php

If this still doesn�t help you � then look at the log files: /includes/modules/payment/paypal/logs (ensure that the folder is writable (ie: chmod 777))

I then had problems when shipping charges were included�.
The same problem as �Zubey� had here.
Whenever tax was added to on either products or shipping. If tax is removed from both it all works fine.

[ITEMAMT] => 0.20
[AMT] => 0.20
[SHIPPINGAMT] => 0.00 **** when this = 0
[TAXAMT] => 0.00 & this = 0, all works fine ****
[L_NUMBER0] =>
[L_QTY0] => 1
[L_NAME0] => TEST Product No.2 $0.20
[L_AMT0] => 0.20

A bit more searching found me this article:
From http://www.zen-cart.com/forum/showpost.php?p=531979&postcount=7
and I changed these settings and it worked:
Config->My Store-> Basis of Product Tax=Shipping and Basis of Shipping Tax=Shipping
and in Module->Shipping (for each shipping module set): Tax Basis = Store

I hope this is the last time I say that �it�s working� and it isn�t!

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