SSAS Tabular incorrect sintax but it is correct

I am trying to use the IN function is analysis services tabular, but it is returning me an error. I tried the same in my co-worker machine and it is working perfectly. I have already uninstalled my data tools 2017 and 2015 and installed again. Now I have only SSDT 2015 and having this problem.

TestMeasureIN:= 
CALCULATE(
COUNTROWS(DimDate),
DimDate[MonthName] IN {"may", "july"}
)

SEMANTIC ERROR: THE SYNTAX FOR 'IN' IS INCORRECT