ValueError: Error when checking target: expected dense_2 to have shape (2,) but got array with shape (75,)

Question

model = Sequential()
model.add(TimeDistributed(Conv2D(64, (3, 3), activation=\'relu\'),input_shape=(10, 255, 255,1)))
model.add(TimeDistributed(Conv2D(64, (3, 3), ac