I was able to resolve this issue by launching the iMac's Keychain Access app and changing the InTuit ID keychain access control to "Allow all applications to access this item". The keychain I changed was created by TurboTax 2020. TurboTax 2021 did not create an InTuit ID keychain, and confused me by asking for the 2020. I had to do a lot of searching on how to find the keychain and manipulate it and my guess is the average TurboTax user doesn't have the computer skills I have to even understand what's going on. My recommendation is to have TurboTax access ItsDeductible in the same way it accesses banks and brokerages without messing around with the Mac keychain.
