Hi
Occasionally also the flight planner will if it considers the waypoint you want to add to far from the current blue course line…will allow you to add the waypoint but actually won’t visually run the blue route thru it making you think it’s not been added ….just double check and if so remove the waypoint you want then add a temporary waypoint closer to the projected blue route line and then re load your chosen waypoint it might then show the route thru your chosen waypoint and you can delete the temporary one……LOL I hope that made sense