Recovery Rebate Tax Credit

I did not get my 2nd stimulus payment for myself or my 16 yr old so when I filed my 2020 taxes I answered the questions about the recovery Rebate credit and the turbotax system said I was due a $1,700.00 as my recovery Rebate Tax Credit.  Now the IRS has amended my tax return and  removed the complete$1,700.00 from my taxes.  Why did the IRS do this and why am I not allow to claim my 2nd stimulus payments when both myself and my son qualify?  Please help. Thank you.