You can reset the settings of your series 5000 cards in the APPolo Control GUI. Just right-click on the related device and choose "Reset Factory Defaults".
APPolo Control page: http://www.lynx-technik.com/en/products/appolo-control/
If you have a RCT5023 controller, you can also use the small hardware reset button located on the device front side
above the USB socket. Press and hold the button for at least 5 seconds.
Default IP addresses:
LYNX Controller: 192.168.1.162 ( RCT5023 )
LYNX Server: 192.168.1.160 ( SERVER_5023 )