I am still figuring out how to resolve this error...
As I have to fixed my first layer of input shape to
`input_shape=(BATCH_SIZE, N_PAST, N_FEATURES)`
I am getting errors on any error for LSTM and GRU

```
    model = tf.keras.models.Sequential([
        tf.keras.layers.LSTM(64, return_sequences=True, input_shape=(BATCH_SIZE,N_PAST, N_FEATURES)),
        tf.keras.layers.Dense(N_FEATURES)
    ])

    model.summary()

    optimizer =  tf.keras.optimizers.SGD(lr=1e-8, momentum=0.9)
    model.compile(
        loss="mse",
        optimizer=optimizer,
        metrics=["mae"]
    )
    model.fit(
        train_set, validation_data=valid_set,validation_steps=100, epochs=100
    )

```