This is a common problem with TurboTax.

Try this:

Start the FILE steps over.

Tell TurboTax you did not file in 2019 - enter AGI of Zero.

I tried entering $0, and it got rejected again but now it's for error code IND-032-04 - which is that my spouse's 2019 AGI does not match. The thing is - we filed married filing jointly last year (2019), so there shouldn't be a separate AGI for her right?

the only other combination is Zero for you and the real AGI for spouse. (never heard of this combo attempt on the forum)

Otherwise, crank up the printer. you will have to file on paper via US Mail

OR

Try a different tax software provider (Not H&R)  It is a product question.
Others have so reported.

Yeah I need to try every permutation lol. I will let you know how it turns out. I'm planning on calling the TurboTax "specialist" once they're open at 8am. 

If I choose another software provider, I assume that I will have to start the whole data entry and filing process again? No chance of importing what I've already done from Turbotax right? 

This is an IRS issue since they are the ones rejecting the return  and  not  a TT one ...  if you filed jointly last year and the true AGI will not work try a zero for both of you ($1 if you filed a non filer return for the stimulus payments last year).  If it is still rejected then your only option is to mail in the return  or   use a local paid tax pro since they do not need the prior year AGI ... only DIY program do (and changing DIY programs will not help).