Cause

A connection's target functions conflict with the function connection points in terms of the entries for the Pressure line / control line property. For example, "Pressure line" was set at the source of the connection, but "Drain line" was set at the target.

Solution

Enter matching data for the Pressure line / control line property for both the source and target of the connection at the function connection points. You set this property in the Connection point logic dialog of the respective function (call up the Properties <...> dialog, select the Symbol / function data tab and click [Logic]).

Refresh the connections and then start a new check run.