You must have answered a question wrong or entered the wrong amount you got for the 3rd Stimulus payment. The Recovery Rebate Credit on 1040 line 30 is only if you didn't get the full amount or qualify for more. The 3rd Stimulus was 1400 per person, 2800 for married. It came out starting in March 2021. Do you have any dependents?
A lot of people answered the questions wrong and tried to claim the credits again. Double check your bank statements to see what the IRS sent you during the year for the 3rd Stimulus payment. And check your IRS account (both accounts if married).
https://www.irs.gov/payments/your-online-account
