Blueprint doesn't work in the new game mode

Hello everyone. I’m kinda new to UE4 and now i’m working on the simle interior scene. To make movement in the room slow and precise I created new game mode with lower parameter of moving speed. After that I wanted to make interactive changeble materials, so I started with creating one small blueprint, where you get a message while approaching some objects. This blueprint doesn’t work in my new game mode, but it works well in the original game mode. Still can’t find the problem. Maybe someone knows what I’m doing wrong… Thank you in advance!

The only way we could see the problem is if you show us the blueprint

You can give more details.