Good catch! Yes when did you file (efile?) 2016?
It is too late to efile 2017 now. You have to use the Desktop program and print and mail 2017.
Then for 2018 you can try to efile by using 0 as the 2017 AGI since you didn't file 2017 on time. That's assuming you didn't file 2016 now using the 2018 online version as xmasbaby answered.
