Error when launching single player build game
[2017.07.13-19.35.22:152][ 0]LogScriptCore:Warning: Script Msg: Attempted to access index 0 from array CallFunc_GetAllActorsOfClass_OutActors of length 0!
[2017.07.13-19.35.22:152][ 0]LogScript:Warning: Accessed None trying to read property CallFunc_Array_Get_Item
ClientSideTopDown_C /Game/Code/Maps/PersistentLevel.PersistentLevel:PersistentLevel.ClientSideTopDown_C_0
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:ExecuteUbergraph_ClientSideTopDown:0C78
[2017.07.13-19.35.22:152][ 0]LogScript:Warning: Script call stack:
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:ReceiveBeginPlay
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:ExecuteUbergraph_ClientSideTopDown
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:Server Init Player
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:ExecuteUbergraph_ClientSideTopDown
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:Server Spawn Player
Function /Game/Code/Controller/ClientSideTopDown.ClientSideTopDown_C:ExecuteUbergraph_ClientSideTopDown