Tax Penalty for 2019 taxes

I have complete my tax return for 2019.  I notice an estimated tax penalty.  Trying to figure out why i got it. The only predictable income i have is social security.  I do get some interest and dividend and some capital gains.  The amounts are unknown until the end of the yer.  I have paid my estimated tax payments based on what I paid in taxes the previous year.  I got that amount from TurboTax.

 

Main increase this year is capital gain near the and of the year.

 

So why do I have this tax penalty?

 

Thank you.