Can you provicde logs? from Saved/Logs in your project directory, crashes usually leave info there what happened.
From breath look, you could try to change GENERATED_USTRUCT_BODY() which is outdated macro to GENERATED_BODY()
Also some tip, create C++ class for your item blueprints, even if it will be empty, it will at least let you use TSubclassOf which will limit selection to item blueprint. You can also add Abstract specifier to it’s UCLASS so C++ item class won’t apper in selection either. I would also declere item properties in C++, it will make items ferther usable in C++