@craigmaloney Okay. That’s the regular balance due notice. No changes IRS side as you’d have a different letter. Your return should show an amount owed on Line 22. If Line 18 (Total Payments) is larger than Line 15 (Total Tax) then you have a glitch. If not then you owe. If you had had an Estimated Tax discrepancy you’d have received a different notice. Most likely it is insufficient withholdings to cover tax due or reduction in credits you qualified for.