Deductions & credits

First of all, did you follow these precise instructions:

1. Select the “Federal ” tab
2. Select the “Deductions & Credits” tab, then select “all deductions”
3. Scroll down to the “Your Home” section, then select Start or Update - Mortgage Interest Credit Certificate
4. Answer “Yes” to “Do You Have a Mortgage Credit Certificate” and select “Continue”
5. Continue adding the information requested on the following screens from the certificate(s) you have and select Continue when finished with each. For the mortgage interest field, only enter mortgage interest that was for the loan covered by your certificate (do not use interest from other loans).
6. If you have more than one certificate, select “Done” when you have finished entering all of them, then press Continue.
7. On the “Qualified Main Home Address, enter the address of the home that you received the Mortgage Credit Certificate for, and select Continue. 
8. If you enter this correctly, you should have a form 8396 generated in your return and you will see this as a non-refundable tax credit on Schedule 3 of your return. 

If, you entered this in as a mortgage interest deduction, you will need to go into your return and remove that information so that the Schedule A can be removed from your return.