Unrecognized type UserWidget

I’m trying to create a small score HUD widget, but I have this error.

I know the simple classes are not suitable for UE4. But this class seems to be in UE4.
I tried to change the class to UUserInterface, but that time I had the error ‘AddToViewPort’: is not a member of ‘UUserWidget’.

How should I fix this?

The GameMode.h file:

The GameMode.cpp file

You wrote “UserWidget” instead of “UUserWidget”!

Oh., well, that’s I’m the fool. I tried to use AddToViewPort instead of AddToViewport function)

You can use Rider for Unreal, I’m using it, it’s very good: