# gateway.payment_method.card_number_issue

> For the complete machine-readable documentation index, see [llms.txt](https://apidocs.chargebee.com/llms.txt).


**gateway**

There is an issue with the card number. This can happen when the card number has an incorrect length, contains typographical errors, is incomplete, or does not pass validation checks.

## Recommended Customer Message

The submitted card number does not include the proper number of digits. Please double-check the card number and attempt the transaction again. If the issue persists, contact your card issuer's support for assistance.

## Root Cause[](#root-cause)

-   **Incorrect card number length:** The entered card number does not meet the required length for the card type (e.g., Visa, MasterCard, Amex).
-   **Typographical errors:** The customer mistyped the card number, leading to missing or extra digits.
-   **Incomplete card details:** The card number entry was submitted before all required digits were entered.
-   **Invalid card number format:** The card number does not pass standard validation checks such as the Luhn algorithm.

## Troubleshooting and Solutions[](#troubleshooting-and-solutions)

-   Verify and re-enter the complete card number carefully, ensuring all digits are correct.
-   Ensure the card number matches the expected format and length for the card type.
-   Retry the transaction after correcting the card number.
-   Ask the customer to contact their card issuer if the correct card number is still being rejected.
-   Implement client-side validation to help prevent submission of incomplete or invalid card numbers.