Invalid Transaction: Declined Code 12 Explained

Few things are more frustrating than having a customer who’s waiting to pay but can’t because of some error code, especially when there is a long line of customers behind them.

Or, if you’re running an eCommerce business, error codes could be dramatically lowering your checkout conversion rates — and you may not even know! Staying on top of error codes and diagnosing them quickly is key to running a successful business.

There are a variety of reasons why your POS may fire a decline code, from fraud to incorrect information, and it’s not realistic to memorize all of the codes and what they mean (although printing out a list of credit cards decline codes and hanging it nearby could be useful).

Today, we’re going to cover the invalid transaction, or declined code 12. Here’s everything you need to know about what it is and what to do about it.

What is declined 12 on a credit card?

Also known as the "invalid transaction" code, a credit card error code 12 is given when the issuing bank does not accept a transaction.

That’s super vague, but it’s true.

The issuing bank is the bank that gave the customer their card, and a declined 12 code is sort of a catch-all for error codes. It doesn’t mean one specific thing, but there are a few common reasons why your POS could be sending it.

Why did the POS give me an invalid transaction message?

Here are a few reasons why you could be getting a credit card code 12:

  1. The card number is incorrect. This is the simplest explanation. Sometimes when a card number is typed incorrectly it can fire back an invalid transaction.
  2. The expiration date is invalid. This could mean it was keyed in incorrectly or it’s expired.
  3. AVS failed. Address Verification Service, or AVS, is a fraud prevention measure implemented by the card member associations such as VISA. They check fields like the zip code against their records to make sure someone isn’t using a card that isn’t theirs.
  4. You tried something strange like refunding a refund. If the system doesn’t know how to handle a request, it could spit back a decline code 12 in response.
  5. The credit card itself is invalid. It’s possible that the card has been canceled or flagged by the credit card company and is coming through as a credit card code 12.
  6. You tried running the card multiple times in a row. Many card associations have measures against multiple quick transactions since it’s often a sign of fraud.

It could be one or a combination of these that is causing your system to fire an invalid transaction. Double-check that it’s not a user error and go from there.

What to do when you get a decline code 12

Decline code situations are always annoying, but follow these steps to resolve them as quickly as possible.

Step 1: Apologize to the customer.

Even if you’re pretty sure it’s their fault, being cordial goes a long way to making this process less frustrating for both parties.

Step 2: Try running the card again.

Take two! Most people try this first anyway, but just in case you haven’t!

Step 3: Double-check the information.

Take a slow read through the code, expiration date, name, and security code. Ask your customer to repeat it if necessary.

Step 4: Double-check the zip code.

It’s possible the customer moved recently and has accidentally put in the wrong zip code. Ask them politely if there’s another zip code possibility.

Step 5: Request a different card.

If you can’t get the card to work, see if your customer minds switching cards for you.

Step 6: Request an alternative form of payment.

See if they can pay by cash or check. If that isn’t an option, don’t just say sorry! Ask to take their name or give them a more direct phone line.

Chances are they’ll have to call their bank to figure things out, so you want to get them right back to the front of the checkout line when they’ve figured it out.

The last thing you want to do is lose a big sale to a competitor over a system error.

Get the rundown on credit card decline codes

Go here for a complete list of credit card decline codes. This is a great page to bookmark!

And if you are running an eCommerce business and want to customize the responses you give customers according to the error code they receive, Visa has some great automated response suggestions, which you can access here.

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