For 2020, I have a single tax client who had AGI of $33,942 on Federal 1040.  After subtracting the $14,050 standard deduction, it leaves her with taxable income of $19,892.  There is no additional tax or credits and no recovery rebate credit.  The program calculated her tax to be zero.  When I check the tax tables, it looks like there should be tax of $2,188.

Does anybody have any ideas why there would be no tax when the taxable income is $19,892 or where in the program I can see how the tax was determined? 

This has me concerned because I have been relying on the program to accurately calculate the amount of tax.