If the date set for withdrawal has passed, you are not alone. The IRS does take some time to withdraw funds and they are backlogged. Try waiting up to a few days before the May 17 deadline before prompting a secondary means of payment. Otherwise, it could end up that you double pay and then have to wait for a refund. Since it is set to be paid, it is best to give the system time to work.
If the payment has still not been withdrawn and you are within a few days of May 17, go to IRS Paying Your Taxes for options or see 2020 Form 1040 Instructions, page 62. Payment options include: