how to fix the below error

[fs,history] = sequentialfs(fun, X_train, Y_train, 'cv',c, 'options', opts, 'nfeatures' ,2);

[KSSV]

Where/ what error?

[khalil ur Rehman]

THis is my Code:

Error using crossval>evalFun (line 488)
The function
'@(train_data,train_labels,test_data,test_labels)sum(predict(fitcsvm(train_data,train_labels,'KernelFunction','rbf'),test_data)~=test_labels)'
generated the following error:
You cannot train an SVM model for more than 2 classes.

Error in crossval>getFuncVal (line 505)
funResult = evalFun(funorStr,arg(:));

Error in crossval (line 351)
    funResult = getFuncVal(1, nData, cvp, data, funorStr, []);

Error in sequentialfs>callfun (line 496)
    funResult = crossval(fun,x,other_data{:},...

Error in sequentialfs (line 364)
                crit(k) = callfun(fun,x,other_data,cv,mcreps,ParOptions);

Error in Transport_SVM (line 27)
  [fs,history] = sequentialfs(fun, X_train, Y_train, 'cv',c, 'options', opts, 'nfeatures' ,2);
  
  

Below is error

Error using crossval>evalFun (line 488)

The function

'@(train_data,train_labels,test_data,test_labels)sum(predict(fitcsvm(train_data,train_labels,'KernelFunction','rbf'),test_data)~=test_labels)'

generated the following error:

You cannot train an SVM model for more than 2 classes.

Error in crossval>getFuncVal (line 505)

funResult = evalFun(funorStr,arg(:));

Error in crossval (line 351)

funResult = getFuncVal(1, nData, cvp, data, funorStr, []);

Error in sequentialfs>callfun (line 496)

funResult = crossval(fun,x,other_data{:},...

Error in sequentialfs (line 364)

crit(k) = callfun(fun,x,other_data,cv,mcreps,ParOptions);

Error in Transport_SVM (line 27)

[fs,history] = sequentialfs(fun, X_train, Y_train, 'cv',c, 'options', opts, 'nfeatures' ,2);