NMI Error 251: Lost Card

What This Means

The bank's fraud rules blocked the transaction. The customer will need to call their issuing bank for more information.

From NMI:
The customer’s card has been reported as lost by the cardholder and the card-issuing bank has requested that merchants keep the card and call the number on the back to report it.

As an online merchant, you don’t have the physical card and can't complete this request – obtain a different payment method from the customer.

Suggested Next Steps

If a new payment method is needed, contact the customer to have them add a new payment method and add it to their Scheduled Order.
You may also choose to add a new payment method for your customer, see "Adding a New Payment Method for Your Customer" below.
Once a new payment method is added to the Scheduled Order, the Scheduled Order should be processed with the new payment method.s.

Adding a new payment method from NMI for your customer?

If you are adding a new payment method for your customer directly to your payment gateway (manually) or need to update the payment method in your Scheduled Order, ensure that you edit the failed Scheduled Order, add a new payment method, and copy the required billing information directly to their Scheduled Order including:

Gateway CustomerId
Current Billing Address
Payment Method Description (optional, but strongly suggested because it is used to display the payment method to your customer)

After Resolving The Issue

Once this issue is resolved, you should use the action to Restart Processing the Failed Scheduled Order.