That credit is a "Non-refundable credit" meaning the credit can lower your tax liability, but once your tax liability is "zeroed" out, there is no credit left to apply. The credit does not get applied as a refund. The credit does not carry-forward to next year.
Could this be the reason you are seeing zero as the credit?
Your tax liability is listed on your 1040 line 16.
Look at Form 8911 for the calculation of the credit.
The credit would be listed on Schedule 3 and flow to your 1040 line 20.
Again, if there is no tax for the credit to lower, the credit won't be useful.
- To View using TurboTax Online:
Select Tax Tools on the left side-bar
Select Tools from that drop-down
Select “View Tax Summary” on the TOOLS CENTER screen
Select “Preview my 1040” which now appears on the left side-bar