The Code Conversion Utility replaced a statically configured Call by Reference node with a placeholder node. This version of LabVIEW NXG does not support statically configured Call by Reference nodes. You cannot directly reference the subVI because it is not supported in this version of LabVIEW NXG.
Statically configured Call by Reference nodes are subVIs with a VI call configuration set to either Reload for each call or Load and retain on first call. The Code Conversion Utility replaces statically configured Call by Reference nodes with a subVI call, but in this case the subVI is not supported in this version of LabVIEW NXG, so the node was replaced with a placeholder node.
Replace the placeholder node with a subVI that has the same functionality. You can also consider using the VI Interop node to call subVIs not supported in this version of LabVIEW NXG. The VI Interop node enables you to call subVIs from the version of LabVIEW you used to create your code.