Free access to the 2016 return has expired unless you used a paid edition last year or this year. I assume you did not use a paid edition last year for your 2017 return, or else it would be unlocked. We can tell you how to pay for your current 2018 return in PLUS or higher, which will unlock all prior returns in that same account.
You appear to be using Online Deluxe. What is the story on your 2018 return? Is that what you are currently using to prepare your 2018 return, or have you already filed your 2018 return and upgraded too far to Deluxe after filing? Are the 2018 and 2016 returns in the same account?
We can tell you how to pay for the Deluxe once your situation is clear. Deluxe is 59.99 for a Federal return, and 44.99 for a state return, if applicable. If you used Free Edition for your 2018 return and upgraded to Deluxe by mistake after filing your 2018 return, we can tell you what to do. If you used Free Edition to file your 2018 return, the minimum payment to unlock prior returns is a PLUS upgrade for 19.99.
