Widget doesn't update when Unit's life amount changes

I made a widget that gets a float health variable from a class called “Viking”, and bind it to a progress bar.
I set the progression bar to 1, yet when the game starts it is blank.

I am using binary version 4.7.6-2513093

EDIT: Seems like a problem with the casting. What other casting could I do so this would work (all examples refer only PlayerCharacter)

Images:

Inside the Viking Blueprint extension:

Inside the Widget:

In Game:

Also, clicking F will do nothing.

I don’t know if this is your problem but you are substracting minus 0.1, substract 0.1 or add -0.1.

Thanks you for the heads up, but nothing changed. I didn’t notice that though.

NOT A BUG.
ANSWER: Unreal Engine 4 Tutorial - 3D Health Bar (NPC's) - YouTube