Error "Objective function values is NaN!"

Hi,

While attempting to train a Logistic classifier on Weka Version 3.6.9 I received the following error

java.lang.Exception: Objective function value is NaN!
weka.core.Optimization.findArgmin(Optimization.java:837)
weka.classifiers.functions.Logistic.buildClassifier(Logistic.java:665)
weka.gui.explorer.ClassifierPanel$16.run(ClassifierPanel.java:1416)

at weka.core.Optimization.findArgmin(Optimization.java:837)
at weka.classifiers.functions.Logistic.buildClassifier(Logistic.java:665
)
at weka.gui.explorer.ClassifierPanel$16.run(ClassifierPanel.java:1416)

Scanning my training data, it looks valid. Has anyone run across this or do you understand the error?

Thank you for any help,
Jeff