Tree Ensemble Learner (Regression) and Missing Values

Hi, rookie here.  I'm trying to run the Tree Ensemble Learner (Regression) node and am getting this error:

ERROR Tree Ensemble Learner (Regression) Execute failed: java.util.concurrent.ExecutionException: java.lang.UnsupportedOperationException: Missing values currently not supported

I thought trees were supposed to work ok with missing values.  Am I supposed to be prepping them some certain way?

Any help would be appreciated.  Thanks!