Business & farm

QBI for Schedule C has been working for quite some time.  Or are you talking about a QBI deduction for a Partnership?

Have you confirmed the deduction is not showing up on Line 9 of your Form 1040?
Have you gone through the error check to check for errors?
Have you confirmed that Line 31 of Schedule C shows a profit?
Have you checked if your tax return shows "taxable income" (not counting Capital Gains) before the QBI deduction (Line 7 minus Line 8 of the 1040, then minus any capital gains)?