Bosch classixx 6 1400 machine stopped working during cycle f21 on display

F21 relates to a motor or control board fault.

However, it is also caused by spikes in the mains and can be spurious.

To reset it.

Turn the appliance knob to the off or reset position, 12 o'clock.

Turn the knob to the 6 o'clock position.

Press and hold the spin button.

While holding it, turn the knob to the 7 o'clock position.

Continue holding the spin button for about 5 seconds.

Release the button.

Turn the knob to off.

When your turn it back on it should have cleared the error code

F21 Motor fault. Call customer service. (NOTE: if the motor brushes are worn, these can be replaced by a competent person).