Addres from parent class to child is not work

When I try to run a simple melee system, I want to use my health system in C ++, and when I try to put ThirdPersonCharacter (child) in GetCurrentHealth, UE4 refuses to do so. NetworkTestCharacter is the parent class for ThirdPersonCharacter. Where I’m wrong, please help.

Thanks in advance to everyone who answers
(My english is not good, sorry)

Знімок екрана 2022-03-11 204118

Sorry guys for strange qustion. I need to put cast…