How to avoid ANFIS warning

The warning I get it is:

Warning: Some input values are outside of the specified input range

My inputs into ANFIS were standardized, and I randomly split my inputs into training/testing so I have something like:

fis=genfis2(train_data)
fismat = anfis(train_data)
output = evalfis(test_data,fismat)

I get the warning when I use evalfis, I can't help it that test_data might contain some outlier value. Should I delete the outliers from my testing set? Thanks