The current online software is ONLY for 2018 returns, which can be e-filed up to October 15, 2019. If you are getting a refund there is not a penalty for filing after the April 15 deadline. If you owe tax due, then your interest/penalty have begun to add up, so get the return prepared and filed as soon as possible. Since you have not filed a 2017 return, when it asks you for a 2017 AGI, use zero.
Online preparation and e-filing for 2017 is permanently closed. Your 2017 return must be printed, signed and mailed.
To file a return for a prior tax year
If you need to prepare a return for 2015, 2016, or 2017 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.