The IRS usually is busy this time of year & maybe behind on deducting payments.
As long as you filed your return or extension on or before April 15, 2019 and you selected April 15, 2019 (or earlier) as your payment date, you won't get penalized for late payment.
To verify the date that Federal funds will be withdrawn from
your account, confirm that funds have been transferred, or cancel the
transaction up to 48 hours before the date you designated the funds to be
debited, call the IRS at 1 (888) 353-4537.
When will my tax payment go through?-------------------
You might want to make sure your return were accepted if you e-filed. You can check your e-file status
How do I check my e-file status?
