When you delete a connection object, the Workflow Manager invalidates all sessions that use these connections. To make a session valid, you must edit it and replace the missing connection.
Open the Connection Browser dialog box for the connection object. For example, click Connections > Relational to open the Connection Browser dialog box for a relational database connection.
Select the connection object you want to delete in the Connection Browser dialog box.
Hold the shift key to select more than one connection to delete.