Apparently a glitch in IRS systems caused some taxpayers to receive notices stating that they owe money for 2023 even though payment was made. Whether you paid by check or electronically, there is a chance you may have received a notice and at this time, there is nothing you need to do as they are working on correcting the matter. As long as you paid in full by the due date, any assessed penalties and interest will be automatically adjusted once your payment has been properly applied.