Did you do a 2016 federal return in the Online version?
How to finish a prior year online return https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-finish-a-prior-year-return-that-i-...
Or you I'll have to buy the 2017 Desktop program and first recreate federal for it to flow to state. You can only buy the download for prior years. You have to buy a separate program for each year. They only sell the last 3 years. You need a full Windows or Mac computer to install it on. Buy the download here
https://turbotax.intuit.com/personal-taxes/past-years-products/
Or go to your state website and get the blank forms to fill out by hand. You will have to print and mail prior year returns.