Reference to self in bp is null

Hello everyone!

My problem is this:
Blueprint call “PC_Character” has to reference my blueprint called “DialogLogic” under DL variable. I have added DialogLogic instance into the world, and set the reference for PC_Character, as you can see in the next picture.

However, playing the level gives me errors “Accessed None ‘DL’ …”, so basically DL is null.
So I even tried manually setting that reference inside DialogLogic blueprint like this, and I get this error:

This is my level blueprint. I even tried setting the reference there, too.

Can anyone help me? I have zero idea what is wrong here… How could a blueprint execute, if there is no instance of it? DialogLogic is derived from Actor bp, so it can be spawned (and thus referenced, right?). I even tried event “Begin Play” in DialogLogic instead of “DelayedStart”, but the reference is still set to null. Got any ideas?