If you set up direct debit to pay your IRS balance due and it is denied because of insufficient funds, you will need to choose an alternate payment method. The IRS will not try to make the withdrawal again once it has been denied.
Be sure to make your payment by April 15, 2019 to avoid a late payment penalty. You can pay your balance due to the IRS with a check or money order or you can pay directly through the IRS Website here: https://www.irs.gov/payments.
Per the IRS: "If a payment is returned by your financial institution (e.g., due to insufficient funds, incorrect account information, closed account, etc.) the IRS will mail a Letter 4870 to the address we have on file for you, explaining why the payment could not be processed, and providing alternate payment options."
For more information, click this IRS link: https://www.irs.gov/payments/pay-taxes-by-electronic-funds-withdrawal.