How to eliminate null or zero values from a bar graph? There is date involved but the null value can be on random dates

Currently, I am building a dashboard which gives manager an option to view the agent performance. Manager can use a slider as an filter to check data upto 30 days. Now as seen in below, if an agent has not logged in on a particular date or if there are no calls, the graph shows the blank value or space. In rows, I have measure value(2 selected) and logged time which is converted to dual axis,

current slider is selected to 16. I want to show the data for actual 16 days not including null.

Below formula is used for parameter:

[Date] <= [Max Date]

and [Date] > DATEADD('day',-[No of Days to Analyze], [Max Date])