Hi,
I can’t see anywhere in your blueprints that you set the blackboard key CanSeePlayer to true. I believe this is the reason the Attack task is never reached. Simply go to your AI blueprint and use that PawnSensing component to update this blackboard parameter (Get blackboard > Set Value as Bool; and give it your key name).
I also suggest that you use AIPerception component instead of PawnSensing. The AIPerception is newer and recommended over the PawnSensing.
Hope this resolves your issue.