No one else can see your tax return. We do not know why the IRS says you owe more. The IRS does not provide any information to TurboTax after you file your tax return. There have been a LOT of people who made mistakes with the recovery rebate credit or the child tax credit for 2021 returns, so those are the first suspects when we hear a story like yours, although your addtional tax owed could also be for many other reasons.
Sometimes we can make an educated guess as to the reason for your reduced refund if you mention specific amounts--for example if your refund was short by $1400 per person---it is likely to be a mix up regarding the 3rd EIP payment. If you received the 3rd stimulus check of $1400 per person in 2021 then you got letter 6475 from the IRS about it. You needed to enter the amount you received. If you already received that money then line 30 on your Form 1040 should have been blank.
If it is short by $1800 or $1500 or a multiple of that amount --- maybe a mixup regarding the advance child tax credit payments. If you received monthly child tax credit payments of $250 or $300 per month between July and December of 2021, then you got letter 6419 from the IRS, and you were required to enter the amount of the advance payments. Only the remaining amount of the CTC should have been on line 28 of your Form 1040.
The IRS knows how much they sent to you for the 3rd stimulus check and they know how much they sent for advance child tax credit payments. If you answered something incorrectly on your tax return then the IRS made a correction that resulted in a reduced refund/tax due for you.
The IRS will send you a letter that explains why your refund was reduced or why you owe more. Meanwhile it might help you to check your online IRS account.
https://www.irs.gov/payments/your-online-account
https://blog.turbotax.intuit.com/tax-refunds/why-is-my-tax-refund-not-what-i-expected-49240/
https://www.irs.gov/newsroom/questions-and-answers-about-the-third-round-economic-impact-payment-top...
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.
Updated IRS FAQ about recovery rebate credit
https://www.irs.gov/pub/taxpros/fs-2022-27.pdf
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
