I’m assuming you started from the Data Flow sample, Data Flow Diagram.
Note how in that sample all of the ports are defined with GraphObject.fromSpot and GraphObject.toSpot values that are appropriate for the side that the port is on.
But note also that that sample assumes that all links are going from a port on the right side of a node to a port on the left side of a node. In your example of the “UL” port on the bottom right “Join” node, the link appears to be going “to” an output-only port. That’s OK, but then you need to make sure that you set both the fromSpot and the toSpot of every port appropriately.