@DDF4 - I suspect here is the confusion... while TT asked you how much was received on Letter 6475, there were actually TWO letters, once addressed to you and one to your spouse....each letter would have noted $2100, which means in TT you should have noted $4200 received.
Do you have a dependent was on your 2020 tax return, but not on 2021?
Go back and check your bank account from last March, I suspect you received $4200,
Since you only indicated you received $2100, and you are due $2800 for a joint return, that put $700 on line 30.
what should have occured is that you entered $4200 as received, were entitled to $2800, but since you are not required to pay back if you received too much stimulus, Line 30 should have been zero.
