If you are in the situation that the tray door is stuck, you can try performing the following:
Disconnect the power cord from the power outlet for a few minutes. Reconnect the power cord and try to operate again as usual.
Ensure that the interconnect cable between the subwoofer and main unit are connected
Note: In the event that you need to remove the disc stuck in behind the tray door, you can use your hand to slide open the tray door by pushing it towards the left manually. Although this action will not damage the tray door, we recommend that this action to be performed only if the disc has to be removed from the set.