4 things to check
///Edit///
To ensure you do have both objects available before opening the page, you need a microflow like this
Hi Steven,
If you want to create a reference between two existing objects, make sure to use the reference selector, by default Mendix won’t add this to the page.
This will let you select an existing range object to your target object.
okay guys i got it! Thank you all for your help
Hi Steven,
The problem is that there is no Range entity created that is associated with your Target entity, so you need to create this entity and link it.
If you want to be able to edit the factor value you need to add a dataview with a Microflow as source.
This microflow creates the Range entity that is associates with the Target entity.
Another option that you have is that you create a Range entity and link it with the Target entity in the flow where you create the Target object.
I hope this helps a bit ;)