"Accessed none trying to read property" keeps showing despite everything works fine (SOLVED)

[Xx_SigmaZ_xX (ςigmaζ)]

So, I was going to make a small diegetic popup menu whenever a player clicks on a certain actor of class and make it disappear when a player clicks on another actor of the same class.
I made the following script which is the only way to make it work I came up with:

And despite everything working just like it should, the error keeps showing.
How can it be fixed?

[Everynone]

What is the actual error message?

[Xx_SigmaZ_xX (ςigmaζ)]

Well, it couldn’t read the property of GetActorOfClass node.
I solved the problem when I found out I placed GetActorOfClass node after IsValid node.
Guess I’m just a dumbass.