Ok ... this year's ONLINE program was for the 2019 returns only and it has been shut down to archive the returns and make room for the 2020 program that will come online in December.
So if you were really working on the 2018 return after 10/15/2019 then you must be using the DOWNLOADED AMENDMENT program ... did you download the program ? Is the 2018 program shutting down ?
I was on the website. The option to amend 2017 and 2019 is there after it logged me out, but the link to amend 2018 logs me out instead of taking me to the link; like a glitch. There's no link to continue where I left off. Wanted to add a form I never received in time. May be easier just to fill out the IRS form and mail it in because in the end it's what has to be done anyway.