You are sharing a map image layer that contains a utility network. When sharing a utility network, all user attribute fields must be set to visible in the layer properties. The field will be indicated by the first <value> parameter and the feature class will be indicated by the second <value> parameter.
- The provided solution will select the layer in the Contents pane. On the ribbon, on the Feature Layer tab, click Fields in the Design group to make the field visible.
For more information on field visibility, see View and edit a layer's fields in the fields view.