Don't try to import it. For Online…..On the Let import your tax info go down to the bottom and pick Change how I enter my form. Then pick Type it in myself.
Enter a 1099-Int under
Federal
Wages & Income
Interest and Dividends
Interest on 1099-INT - Click the Start or Update button
Does the 1099 INT show the amount and the box #? It probably goes in box 3.
If you're trying to import your 1099-INT if your payor is not in the dropdown menu, they're not a partner with TurboTax and you'll have to manually enter your 1099-INT.
To enter in your interest, follow the instructions below:
Refer to the TurboTax articles Where do I enter Form 1099-INT?