Cause

You specified in the Cable Properties dialog that only one PE / PEN conductor is permitted in the cable. The cable actually has several PE / PEN conductors, however.

Solution

Possibility 1

Change the potential type for one of the multiple assigned conductors.
To do this, double-click the cable source component and select the Symbol / function data tab in the Properties <...> dialog. Click [Logic]. In the Connection point logic dialog, assign the function connection point 2 under Potential type a new value, for example, "undefined".

Possibility 2

If you want the cable to have multiple PE / PEN conductors, double-click the cable definition line in the schematic and select the Allow multiple PE conductors check box in the Properties <...> dialog.

Refresh the connections and then start a new check run.