Can''t enter 2019 Q4 estimated tax paid

[JBuff3]

I successfully entered Q1, Q2, Q3 estimated tax paid in 2019 Turbo Tax Deluxe.   But it will NOT allow me to enter Q4 estimated tax paid.  I tried changing the payment date without success.  I spent a hour on-line with Turbo Tax agent without getting an answer.  I uninstalled my TT2019 Deluxe then downloaded/re-installed without success.   There is no other apparent problem in TT2019 nor in any other application on my computer.  

What must I do to enter my Q4 estimated tax in TT2019 Deluxe?

[ee-ea]

Verify the dates

Q1 due 4/15/19

Q2 due 6/15/19

Q3 due 9/15/19

Q4 due 1/15/20 unless you file and pay before 1/31/20

[dmertz]

"Will not allow" does not say anything about what TurboTax does in response to your attempt to enter the date.

What are you typing and how does TurboTax respond?

Are you trying to use the numeric keypad without the being NumLock on?