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:

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: ( RCT5023 )

LYNX Server: ( SERVER_5023 )