Calculation of last 15 month from the point another measure = 1

[RURURU]

hello guys, 
i have issue with dax measure.. 
i need a dax measure who calculate all fees from last 15 month but i need him to starts summring from the individual point for each payer which is dax measure as well who have a 1 or 0 value 
until now i tried a lot of versuin like that and keep getting this error 
A function 'PLACEHOLDER' has been used in a True/False expression that is used as a table filter expression. This is not allowed.

test measure  =

VAR LastChangeDate =

    CALCULATE (

        MAX (dimDate[Date]),

        [churn] = 1,

        dimDate[Date] > EDATE ( TODAY(), -15 ))

RETURN

    CALCULATE (

        [All Fees],

        FILTER (

            ALL ( dimDate[Date] ),

            dimDate[Date] > EDATE ( LastChangeDate, -15 )

                && dimDate[Date] <= LastChangeDate

        )

    )
try as well to use dateadd but keep getting this error.
how can i sum the last 15 month from the point [churn] = 1 

[johnt75]

You need to iterate over the individual payers, so that the calculation is done for each row. Try

test measure =
SUMX (
    VALUES ( 'Payer'[Payer ID] ),
    VAR LastChangeDate =
        CALCULATE (
            MAX ( dimDate[Date] ),
            [churn] = 1,
            dimDate[Date] > EDATE ( TODAY (), -15 )
        )
    RETURN
        IF (
            NOT ISBLANK ( LastChangeDate ),
            CALCULATE (
                [All Fees],
                FILTER (
                    ALL ( dimDate[Date] ),
                    dimDate[Date] > EDATE ( LastChangeDate, -15 )
                        && dimDate[Date] <= LastChangeDate
                )
            )
        )
)

[RURURU]

A function 'PLACEHOLDER' has been used in a True/False expression that is used as a table filter expression. This is not allowed. 
getting this error again 

[johnt75 · Accepted solution]

Try

test measure =
SUMX (
    VALUES ( 'Payer'[Payer ID] ),
    VAR LastChangeDate =
        CALCULATE (
            MAX ( dimDate[Date] ),
            FILTER (
                ALL ( dimDate[Date] ),
                [churn] = 1
                    && dimDate[Date] > EDATE ( TODAY (), -15 )
            )
        )
    RETURN
        IF (
            NOT ISBLANK ( LastChangeDate ),
            CALCULATE (
                [All Fees],
                FILTER (
                    ALL ( dimDate[Date] ),
                    dimDate[Date] > EDATE ( LastChangeDate, -15 )
                        && dimDate[Date] <= LastChangeDate
                )
            )
        )
)