model = Sequential()
model.add(Masking(mask_value=0, input_shape=(timesteps, features)))
model.add(LSTM(100, dropout=0.2, recurrent_dropout=0.2,return_sequences=True))
model.add(Dense(features, activation='softmax'))
model.compile(loss='categorical_crossentropy', optimizer='adam', metrics=['accuracy'])
model.summary()

ValueError: Error when checking target: expected dense_1 to have 3 dimensions, but got array with shape (14, 5)

ValueError: Invalid shape for y: (14, 1, 5)

model.add(TimeDistributed(LSTM(100, dropout=0.2, recurrent_dropout=0.2,return_sequences=True)))

TypeError: unsupported operand type(s) for +: 'NoneType' and 'int'