Accessed none trying to read directional light reference

I have this error when i try to run my day/night cycle, as you can see, it says the variable sun it is accessing none, when all that variable is, is a directional light reference, any help?

Your sun reference is invalid what is your default value the sun in your map? Or where/when do you set this object reference?

the default value is just the directional light, and i set it at event begin play

How about a screen shot of your blueprints setting this variable?