Accessed None Trying to Read Property while doing AI so it can see me

Hi guys i would like some help with this, i was doing random Roaming enemy using Paragon characters but they dont do anything and when they see me after closing the editor this error pops up for each time they tried to see me.

Blueprint Runtime Error: “Accessed None trying to read property CallFunc_GetBlackboard_ReturnValue”. Blueprint: EnemyAIController Function: Execute Ubergraph Enemy AIController Graph: EventGraph Node: Set Value as Bool

Nvm fixed it.

Stupidest error ever, i havent set which behavior tree to use

Try watching video #27 in this list. Hopefully helps you get an idea of what the issue is.

Also, because you are using blackboards your situation may be a bit more complex…so have you made sure to use the node “run behavior tree”? Is the blackboard you set up for those AI the same one that has that named boolean variable? You do need to assign specific behavior trees and blackboards if you have multiple.