In the regular Turbo Tax Free Edition, information that you can enter is limited now.  Under the new tax laws, there are no more simple Form 1040EZ or 1040A's.  Everything goes on a little Form 1040 that has six extra "schedules" with it, and if you need any of those schedules, you are not able to use the Free Edition.  

https://www.irs.gov/forms-pubs/about-form-1040 

See if you have anything on schedule 3 https://www.irs.gov/pub/irs-pdf/f1040s3.pdf