X EtherCAT slaves found

This communicate may indicate a motor controller failure.

Properly working base motor controller should look like this:

Motor controller

If you see that in your case no all LEDs are turned on you should check cables and connections. If the problem remains you should check and if necessary replace base control board fuses as described here Base Controller Fuses. If this does not help then your motor control board may be broken.

Opening the youBot covers can void you warranty. Therefore before you proceed contact youBot technical support.