Turbotax doesn't care that you did or didn't e-file in the past. The IRS may have rejected the return for lack of a correct identifying PIN or some other reason, we don't know the reject message.
When e-filing you need a 5 digit e-file PIN or the taxpayer's adjusted gross income (AGI) from last season. If the taxpayer didn't file or filed late, the AGI may not be in the system, but if you filed on time it should be. Make sure you are using the right number from the right form. https://ttlc.intuit.com/questions/1900840-how-do-i-find-last-year-s-agi
If the customer has never e-filed before, they can choose a self-selected 5 digit e-file PIN the first year they e-file. They can then use the same PIN year after year instead of using their AGI from the previous year.
Also be aware if using Turbotax Online, filing two returns requires 2 separate online accounts, with different user names and passwords (the email address for notifications can be the same). You will also pay two separate fees, unless you qualify to file for free. Families with more than one tax return to file will often find it is more cost effective to buy Turbotax on CD from Staples, Costco, Walmart, or similar retailers, since it is usually discounted, and allows filing of multiple returns.
