Accessed None Errors While Using A Reference Variable...

Hello , … I was just trying to setup Inventory using the tutorial given by ue4 but i am not implementing the pickup function and i am doing it in an another widget ( i have a widget which shows health and stuff but im not using that one ) so i have to use this visiblity thing but im having some errors
Blueprint Runtime Error Accessed None trying to read property Reference from function ‘ExecuteUbergraph_BP_C_Male’ from node Branch in graph EventGraph in object BP_C_Male with description Accessed None trying to read property Reference

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Blueprint Runtime Error: Accessed None trying to read property Reference from function: ‘ExecuteUbergraph_BP_C_Male’ from node: Set Visibility in graph: EventGraph in object: BP_C_Male with description: Accessed None trying to read property Reference

Here Are The images :-

When do you fire that Custom Event? (ActivateInventory)

i am using the custom event (ActivateInventory) in order to create widget and add it to the viewport.also i have promote the create widget to a variable and named it " Reference " and i am using it to refer to the inventory in both the first and second image

I am using the custom event
(ActivateInventory) in order to create
widget and add it to the viewport.also
i have promote the create widget to a
variable and named it " Reference "
and i am using it to refer to the
inventory in both the first and second
image

That’s great but it does not answer my question. Nowhere in your screenshot can we see the Event being triggered. Having it in the graph does not mean that you’re using it, you need to call it, too. You’re seeing those errors because the menu never gets created and the Reference variable remains invalid.

The ‘I’ button tries to show / hide a menu that does not exist.

Have a look at this one:

Do note how the IsNotValid is calling the CustomEvent