https://github.com/ros-planning/navigation2/blob/61710875ed1d73e807b7cd1a9e577d995f2e4ead/nav2_waypoint_follower/src/waypoint_follower.cpp#L75

Action name "FollowWaypoints" should be changed to "follow_waypoints".

This is the problem that was pointed out in #1484 (comment) .