title: Keras - "ValueError: Error when checking target: expected activation_1 to have shape (None, 9) but got array with shape (9,1)
body: <p>I'm building a model to classify text into one of 9 layers, and am having this error when running it. Activation 1 seems to refer to the Convolutional layer's input, but I'm unsure about what's wrong with the input.</p>
  
  <pre><code>num_classes=9
  Y_train = keras.utils.to_categorical(Y_train, num_classes)
  #Reshape data to add new dimension
  X_train = X_train.reshape((100, 150, 1)) 
  Y_train = Y_train.reshape((100, 9, 1)) 
  model = Sequential() 
  model.add(Conv1d(1, kernel_size=3, activation='relu', input_shape=(None, 1))) 
  model.add(Dense(num_classes)) 
  model.add(Activation('softmax')) 
  
  model.compile(loss='categorical_crossentropy', optimizer='adam', metrics=['accuracy']) 
  model.fit(x=X_train,y=Y_train, epochs=200, batch_size=20)
  </code></pre>
  
  <p>Running this results in the following error:</p>
  
  <blockquote>
    <p>"ValueError: Error when checking target: expected activation_1 to have shape (None, 9) but got array with shape (9,1)</p>
  </blockquote>