Make sure you are using the AGI listed on your 2018 1040 line 7.
If you filed Married Filing Jointly last year, be sure you didn't switch the order of your names on your tax return this year.
See this FAQ for more reasons
https://ttlc.intuit.com/community/rejections/help/what-if-i-entered-the-correct-agi-and-i-m-still-getting-an-e-file-reject/00/27031