Sounds like the IRS thinks you got the $1400 already.
LOTS of people have made mistakes this year with the recovery rebate credit by "forgetting" that they received the $1400 per person stimulus checks last year. They answered no to the questions for the recovery recovery rebate credit and put the $1400 per person on line 30 of their returns. But you cannot get it twice, so the IRS removes it when it is there by mistake. The IRS sent letter 6475 showing that you received the 3rd stimulus check.
It is very important that if you filed a joint return—-the IRS sent letter 6475 to EACH spouse. You had to enter the total amount received. Many people misunderstood and entered only the amount from one of the letters.
Try checking your online account with the IRS (and if you filed a joint return—check for BOTH of you)
https://www.irs.gov/payments/your-online-account
Does the IRS show that you received a $1400 per person stimulus or EIP check in 2021? Did you receive it? When you were asked on your tax return did you say no? Was there $1400 per person on line 30 of your tax return?
If the IRS says you got $1400 per person last year but you did not receive it you can have it traced.
LOST THIRD STIMULUS CHECK
If you need to trace a payment that the IRS says has been issued to you, mail or fax a completed IRS Form 3911, Taxpayer Statement Regarding Refund.
TurboTax does not get any information from the IRS after you file your tax return, so no one at TT knows why your refund was less.