What exactly are you doing in regards to 2017 AGI? Are you trying to efile a 2018 return and got an efile rejection notice? If an efiled return is rejected for 2017 AGI reasons, it is the IRS that is doing the rejecting.
When did you file the 2017 return? If you filed it real late, such as November 2018 or later, then use an AGI of 0.
Otherwise, be sure you are using the 2017 AGI from the original 2017 return, not an amended one.
If a joint return, both spouses use the same total AGI. Do not split it.
If all else fails, then before giving up and mailing the return, try efiling with an AGI of 0 anyway. We have seen it occasionally work, even when there's not a good explanation.
