The IRS denied my 2020 EIC that was calculated by TurboTax. Why?

[LINGDOLING]

Used 2020 Turbotax for Desktop and the software calculated a $323 Deductible part of self-employment tax on form Schedule-1 line 14 which was also on Form 1040 line 10a.  Have a Charitable contributions of $300 on line 10b. So, my total adjustment income is $623.  Have a self employment income of $6,500 minus total expenses of $1,920 which equal to $4,566.  Add bank interest of $19. So, total income is $4,585. My Adjusted gross income is $3,962 ($4,585 - $623). have a Standard deductions (in 2020) of $12,400.  My self-empployment tax from Schedule-2 line 4 is $645 which is also on form 1040 line 23 & 24.  Earned income credit (EIC) line 27 of form 1040 is $323. My total payments form 1040 line 33 is $323 which is the EIC amount.  Amount I owe on my 2020 Federal Tax Return is $645 - $323 equals $322 amount you owe on form 1040 line 37.  Paid the $322 when I filed my 2020 Federal Tax Return.  Just got a letter from the IRS telling me to pay $389.48 (with interest added). The IRS denied my Earned Income Credit of $323, that was calculated by TurboTax.  I still don't know why the IRS denied it. Been checking online and can't seem to find if there were changes to the EIC in 2020.  Please Help!  THANKS!