The Online product is only available for the current year filing. To file previous years you will need to use the Desktop product. Please click here to get started: https://turbotax.intuit.com/personal-taxes/past-years-products/.

This link has some helpful information on filing previous years returns: https://turbotax.intuit.com/tax-tools/tax-tips/IRS-Tax-Return/How-Do-I-File-Back-Tax-Returns-/INF145...