Magento – How to handle $0 dollar transactions

authorize.net

My store offers some 100% off coupons, including shipping. When I try to checkout, it asks for my credit card information. When I try to place the order, it comes back saying "Invalid amount for authorization". I'm using Authorize.net.

Any ideas?

Best Answer

By default Magento should display a message saying "No payment information required" if you have the free payment method enabled. This method only displays when there is a $0 checkout.

I'm demonstrating this on a stock Magento 1.8CE, but have used this as far back as 1.2CE:

From System > Configuration > Payment Methods, ensure that the Zero Subtotal Checkout method is enabled:

enter image description here

And now you need to ensure that you haven't made any template modifications in the checkout theme that would prevent all enabled payment methods from appearing.

Here I'm checking out with a $0.00 item in the cart, and $0.00 flat rate shipping:

enter image description here

Related Solutions

Magento – AVS mismatch when billing and shipping addresses are different

I believe this is a setting for the client to set in their authorize.net account if they are okay with shipping to non-billing addresses:

http://www.authorize.net/content/dam/authorize/documents/merchant_guide.pdf

Refer Chapter 3 (Integration Settings)

Magento – Authorize.net Direct Post hash validation failed

As defined in app/code/core/Mage/Authorizenet/Model/Directpost.php, this exception is thrown if any portion of the below evaluates as false:

if (!$this->getConfigData('trans_md5') || !$this->getConfigData('login') ||
    !$response->isValidHash($this->getConfigData('trans_md5'), $this->getConfigData('login'))
) {
    Mage::throwException(
        Mage::helper('authorizenet')->__('Response hash validation failed. Transaction declined.')
    );
}

So, it's one of three things:

You have no trans_md5 defined in the config tree payment/authorizenet_directpost/trans_md5
There is no login defined in payment/authorizenet_directpost/login
The method isValidHash is returning false

The method isValidHash returns false because there is an issue with either the generated hash (e.g. your API Login/Key are wrong, generate a new one and re-enter) or the amount of the transaction somehow differs between Authorize and your system.

The latter is less likely, but because generateHash in Mage_Authorizenet_Model_Directpost_Response uses the transaction amount as part of the hash, it's a potential factor here.

Best Answer

Related Solutions

Magento – AVS mismatch when billing and shipping addresses are different

Magento – Authorize.net Direct Post hash validation failed

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