Due to high e-filing volume, the IRS may not be able to debit your payment until after the deadline. Also, it can take your bank another few days to post the debit to your account.
As long as you filed your return or extension on or before April 18, 2017 and you selected April 18, 2017 (or earlier) as your payment date, you won't get penalized for late payment. Please see the FAQ below for more information.
When will my tax payment go through?
https://ttlc.intuit.com/replies/3299924
