if you really wish to teleport from 1 to 2 and from 2 to 1 you need to know that your code from trigger box 2 teleports player to trigger box 3 and not to trigger box 1 (because you plugged the location from trigger box 3 in the new location field), and that’s why you can’t go back to the first teleporter
something that may cause trouble: remember that “OnActorBeginOverlap” fires whenever anything overlaps it, it may cause some unwanted behaviour, if your bullet overlap the box it will teleport the player, even if the player is far away from the trigger box.