Yes, it uses interface functions, I’ll give a part of the big picture here.
There is an actor component called “BP_CanInteract” (it is the one which have an issue with) It embeds a variable of type “BP_Interactable” (if you want to see a picture of what it looks like check the first post)
There is an actor called “BP_Interactable” which purpose is to act as a “base class” for interactive elements in the game. This class is “bound” to a blueprint interface called “BPI_Interactable” (there is just one function called “Interact” in there), the “BP_Interactable” does not have any implementation of this function (is this the culprit ?), since it’s meant to be a “generic” base class.