1)  Your taxable income has been reduced to zero already.  (one can still owe a penalty in some situations)

2) Your total of all charity $$ is over  the % of AGI limit for the type of donation You entered.   Depending on what was donated, your donations claimed this year are limited to 60%, or 30%, or 20% of AGI....with excess not allowed are carried over to next year.  

It is very common.  Please read this post from user xmasbaby0 for the explanation: Charitable deductions.  You may also read this: Donations

Here are the 2019 standard deductions:

Single taxpayers and married taxpayers who file separate returns can claim a $12,200 standard deduction.

Married couples filing jointly can claim an amount that's twice as large, $24,400, and

Taxpayers filing as "head of household" (single individuals with dependents) can claim a standard deduction of $18,350.

@benkue