If you are encountering the 'PayPal gateway has rejected request. The totals of the cart item amounts do not match order amounts (#10413: Transaction refused because of an invalid argument.)' error in Magento 1.9 when using PayPal as a payment gateway, you are not alone. Let's delve into the potential causes and provide you with some solutions.

Understanding the Error

In Magento 1.9, this error typically occurs when the totals of the cart item amounts do not match the order amounts.

The inconsistency in the amounts is the main culprit behind this rejection by the PayPal gateway.

This can lead to frustration for both merchants and customers, as the payment process fails to proceed.

Possible Causes

1. Tax Calculation Discrepancy

One common reason for this error is a discrepancy in tax calculation between Magento and PayPal.

It's crucial to ensure that the tax calculations are consistent between the two platforms.

Any disparities in tax amounts could result in the rejection of the transaction by PayPal.

2. Shipping Amount Mismatch

Another potential cause is a mismatch in the shipping amounts.

If the calculated shipping costs differ between Magento and PayPal, it can trigger the #10413 error.

Double-check and compare the applied shipping costs on both platforms to identify any discrepancies.

3. Currency Conversion Issues

In cases involving international transactions with currency conversion, discrepancies in the converted amounts can lead to the PayPal error.

Ensure that the currency conversion rates are accurately set up and synchronized between Magento and PayPal to avoid any invalid argument rejections.


1. Verify Tax and Shipping Configurations

Inspect the tax and shipping configurations in your Magento backend.

Ensure that the tax rules and shipping methods are accurately set up and aligned with your PayPal settings.

Consistency in these configurations can help mitigate the error.

2. Check Currency Conversion Settings

Review the currency conversion settings in both Magento and PayPal.

Verify that the conversion rates are up to date and consistent.

Adjust any discrepancies in the currency conversion to minimize the risk of transaction refusals.

3. Update and Test PayPal API Credentials

Make sure that the API credentials for PayPal integration in Magento are updated and valid.

Test the credentials to confirm connectivity and authorization with your PayPal account.

Outdated or incorrect API credentials can lead to transaction failures.


Encountering the PayPal Error No.10413 in Magento 1.9 can be challenging, but understanding the potential causes and implementing the recommended solutions can help streamline the payment process and enhance the overall customer experience.

By addressing tax, shipping, and currency conversion discrepancies while ensuring the integrity of PayPal API credentials, you can mitigate the risk of transaction refusals and facilitate smoother payment transactions for your Magento store.

Remember, a thorough inspection of tax, shipping, and currency settings coupled with updated API credentials can pave the way for seamless PayPal transactions within your Magento 1.9 environment.

Here's to optimizing your PayPal integration for a more efficient and reliable payment experience!