DAX Issue in Power BI Designer

Hi All,

This is a very specific question.  In Power BI Designer, I'm working with exam data where the column headers are different course titles along with the assignment (ex: ADAExam, ADAAssignment, etc).  Using DAX, I want to create a measure that will average an individual column (ADAExam) that filters out blank cells as well as the value 0.  I know I can get around blank cells using AVERAGEA, but I'm not positive I'm filtering around 0 properly.  What I have is:  CALCULATE(AVERAGEA(Table1[ADARes]), Table1[ADARes] <> 0)

Designer seems to accept that, but when I drag the measure out into the canvas, it gives a warning sign saying that it "cannot retrieve the data for this visualization."

Any help with the formula or insight as to why this is happening would be very helpful!

Thanks