Character data to a widget

Hi mans!

I have very big problem.

How i read and write a variable in a PlayerPawn blueprint class from a Widget B.C.?
I created a PlayerPawn reference in a widget, but i have this error message:

Error Blueprint Runtime Error: Attempted to assign to None from
function:
‘ExecuteUbergraph_Widget_CharacterChange’
from node: Set CharacterMesh in graph:
EventGraph in object:
Widget_CharacterChange with
description: Attempted to assign to
None

Please help me!