Need to change "December 23, 2019 at 08:31PM" to a date Google Sheets recognize.
You can use the following formula for eg. cell
Then copy and paste on top
Values only. Then change the format.
December 23, 2019 08:31PM is what you need.
Please make sure you don't have the cell formatted as text. You can have it either at
Automatic or as
Read more about custom date and time formats