Cause

A part placement that is the target of a routing connection was moved in the layout space, so that the routing connection virtually ends up "hanging in the air" at one end.

Solution

Possibility 1

1. Locate the moved part placement in the layout space using the Go to (graphic) function from the popup menu in the Message management dialog.
   
   The routing connection in question is highlighted in color in the layout space.
   
2. Route the connections again.
3. Then start a new check run.

Possibility 2

1. Locate the moved part placement in the layout space using the Go to 2nd coordinate functionality from the popup menu in the Message management dialog.
   
   The part placement is highlighted in the layout space.
2. Move it back to the old position, so that it becomes the target of the routing connection again.
3. Then start a new check run.