Root Cause

• Invalid or expired authentication credentials: The API key, authentication token, or credentials used for the transaction are invalid or expired.

• Missing authentication details: Required authentication headers or parameters were not included in the transaction request.

• Incorrect gateway configuration: The merchant's payment gateway account is not properly configured for the requested operation.

• Revoked or inactive API credentials: The credentials used have been revoked, deactivated, or are no longer authorized for transaction processing.

Troubleshooting and Solutions

• Verify that the correct API key or authentication token is being used and that it has not expired.

• Ensure all required authentication details are properly included in the transaction request headers or payload.

• Check that the payment gateway account is active and configured correctly for the requested transaction types.

• If credentials were recently updated, confirm that the latest values are being used in the integration.

• Contact the payment gateway support team to regenerate or reactivate API credentials if the issue persists.