Formula help

Hello everyone - 

I'm trying to make a dashboard and have created a formula as below:

Total KM1 Forecast Amount = CALCULATE(SUM('Invoice&POTracker'[KM1 forecast Amount (25%)]), YEAR('Invoice&POTracker'[KM1 Forecast Date]) = YEAR(TODAY()) && MONTH('Invoice&POTracker'[KM1 Forecast Date]) = MONTH(TODAY()))

 

I then try and replicate this for KM1 Invoiced Amount adding additional criteria and when I click save it deletes the formula and then just says column?

 

What am I doing wrong?