@maryjean1002
The IRS notice is not saying that you should have paid estimated tax. It's saying that you entered estimated tax payments on your tax return, but you did not make those payments. On the tax return that you filed, is there an amount on Form 1040 line 26? That line is for estimated tax that you paid for 2021. If you did not pay estimated tax, line 26 should be blank. From the figures that you gave, it looks like line 26 is probably $1,200. But you said you did not pay any estimated tax, so there shouldn't be anything on that line. If line 26 is $1,200, that's the error in your tax return. You claimed that you paid $1,200 of estimated tax, and took credit for that amount on your tax return, but you did not actually pay the $1,200.
