If you paid the sales taxes in 2016, you'll need to amend your 2016 return to claim the taxes as a deduction. You can't claim taxes in a prior year on a current-year return.
Please see the
TurboTax FAQ "How to amend (change or correct) a return you already
filed," below, for instruction on how to amend your previously-filed 2016 tax
return.
https://ttlc.intuit.com/replies/3288565
