Error Attempted to access missing property 'CurrentWeapon'

Hello there!

I try to fix an issue I always getting. I want to display my Ammo in an UI.
The stange issue is, if I remove the pins and re assigne them, it works for a while until the error appears again.

Error:
Blueprint Runtime Error: “Attempted to access missing property ‘CurrentWeapon’. If this is a packaged/cooked build, are you attempting to use an editor-only property?”. Node: Return Node Graph: GetCurrentAmmo Function: Get Current Ammo Blueprint: UI_Ammo
Blueprint Runtime Error: “Accessed None trying to read property CurrentWeapon”. Node: Return Node Graph: GetCurrentAmmo Function: Get Current Ammo Blueprint: UI_Ammo

This is my function to get the amount:

and this the Event graph:

What did I do wrong?

Thanks in advance!

Br,
JR