The owner creates a Dataflow which has an ODBC connection through Enterprise gateway and schedules a refresh,
Dataflow is taken over by some other user who changes the ODBC connection pointing to a different server,
Creator tries to again take over the same dataflow.
At this moment gateway requires both old and new connection to exist under Gateway sources (even though query only uses new connection). In case the old source is no longer available, we are no longer able to use the enterprise gateway since it requires old data source connection even though it's no longer listed nor used inside a query.