undefined

The  date field you are using in the slicer should come from the date table. I think you don't have date table. If you use a date table you will be much happier in the future. I will paste code for a Date table. If you go to Modeling>New Table> then put the code in. Afterwhich you Mark the Date Table by selecting the Date field and validating on this. Then you connect your Date Table to your sheet one on Date Table Date to Sheet1 Date.

Then don't use the Sheet1 date field anymore. Use Date Table date field. I hope this makes sense.

Here is Date Table Code to start with:

Dates =

-- Specify a start date and end date

VAR StartDate = Date(2021,1,1)

VAR EndDate = Today()

VAR FiscalMonthEnd = 6

-- Generate a base table of dates

VAR BaseTable = Calendar(StartDate, EndDate)

-- Add the Year for each individual date

VAR Years = ADDCOLUMNS(BaseTable,"Year",YEAR([Date]))

-- Add the calendar month and other month related data for each date

VAR Months = ADDCOLUMNS(

    Years,

    "Month",MONTH([Date]),

    "Year and Month Number",FORMAT([Date],"YYYY-MM"),

    "Year and Month Name",FORMAT([Date],"YYYY-MMM"),

    "Fiscal Year", IF( FiscalMonthEnd = 12, YEAR([Date]), IF( MONTH([DATE]) <= FiscalMonthEnd, YEAR([DATE])-1, YEAR([Date]))),

    "Fiscal Month", IF( FiscalMonthEnd = 12, MONTH([Date]),

        IF( MONTH([Date]) <= FiscalMonthEnd, FiscalMonthEnd + MONTH([Date]), MONTH([Date]) - FiscalMonthEnd))

)

-- Add the Quarter and other quarter related data for each date   

VAR Quarters = ADDCOLUMNS(

    Months,

    "Quarter",ROUNDUP(MONTH([Date])/3,0),

    "Year and Quarter",[Year] & "-Q" & ROUNDUP(MONTH([Date])/3,0))

-- Add the Day and other day related data for each date   

VAR Days = ADDCOLUMNS(

    Quarters,

    "Day",DAY([Date]),

    "Day Name",FORMAT([Date],"DDDD"),

    "Day Of Week",WEEKDAY([Date]),

    "Day Of Year", DATEDIFF (DATE(YEAR([Date]),1,1), [Date], DAY) + 1)

-- Add the Week (assuming each week starts on a Sunday) and other week related data for each date   

VAR Weeks = ADDCOLUMNS(

    Days,

    "Week Of Month (Sunday)",INT((DAY([Date])-1)/7)+1,

    "Week of Year (Sunday)",WEEKNUM([Date],1),

    "Year and Week (Sunday)",[Year] & "-W" & WEEKNUM([Date],1))

-- Add an 'Is Working Day' column which will be true for all days but Saturday and Sunday.

var WorkingDays = ADDCOLUMNS(

    Weeks,

    "Is Working Day", NOT WEEKDAY( [Date] ) IN {1,7})

RETURN WorkingDays

Model should look like this: