When you file a joint return the AGI is the same for both spouses. If you filed a joint 2019 return use the amount on line 8b for each of you.
When did you file 2019? If it was late in the year or you mailed it, try putting in zero for the AGI. And see, https://ttlc.intuit.com/community/rejections/help/what-if-i-entered-the-correct-agi-and-i-m-still-ge...
How to correct the AGI
If you can’t get it to efile you will have to print and mail it.
How to mail a return from the Online version
Be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.
For AGI Reject code 031
Wait a minute. How did you file last year? Did you both file all your income on the same Joint return? You said wife filed Joint. What about You? Did you file one return together?