How to solve the error "some observation could not be classified" in using multi svm?

Here,the error lines

    % code
Error using svmclassify (line 156)
Some observations in TEST could not be classified. This is probably caused by NaN values in the data. Logical
response can't contain missing values. You can convert the logical response into NOMINAL or double.
Error in multisvm (line 29)
            classes = svmclassify(svmStruct,tst);
Error in Main>pushbutton7_Callback (line 382)
result = multisvm(Features_Four,labels,FeatureVector);
Error in gui_mainfcn (line 95)
        feval(varargin{:});
Error in Main (line 42)
    gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)Main('pushbutton7_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback.