If your return was rejected for the 2017 AGI it doesn't matter anymore ... you can no longer efile a 2018 return ... it must be printed, ink signed and mailed. And because you filed the 2018 return late when you go to efile the 2019 use a ZERO for the 2018 AGI since you filed it late ( may be the same issue you had for the 2017 AGI if you filed that return late).
