A couple of possibilities… the flare is only visible in the game view, so check there if you have only looked in the scene. Also, the direction of the light’s Z axis (blue arrow) has to be pointing towards the camera for the flare to be seen.
Make sure that the ‘Fx’ button for the Scene viewport is on. Go here for details.
Make sure you don’t have a collider blocking the trace path between the camera and the flare. Colliders will block flares.
Sometimes you just need to select the flare in the viewport to refresh it.
The axis of the light only applies to a directional light, not a point light. Further, it’s more about which way your camera is facing, and not reliant a specific axis.
However, the most accurate result as andeeee indicated is to view it in the Game viewport.