Overlay not appearing

I'm trying to create an overlay that is shown to each player every time they enter the server for a certain amount of time, and I've tried several things and with messages I checked that the code is running as I thought but for some reason the overlay is not shown. I have created the overlay and three procedures for this management which are the ones shown in the image:

Image

I also tried to change the NBT tags to PLAYER_PERSISTANT variables but the result is the same, the overlay is not shown. Can someone help me? Or know another way to do this? 

Thanks