MeshPhongMaterial can be tricky because it requires a light source to show the true color. It's likely the mesh is still red, but it just looks dark blue since there's so little light on it.

Try creating a PointLight and placing it in front of your mesh. Pretty sure that'll brighten it up and show the red color.

Here's some docs to get you going: https://threejs.org/docs/#api/en/lights/PointLight

const light = new THREE.PointLight( 0xff0000, 1, 100 );
light.position.set( 50, 50, 50 );
scene.add( light );

Okay perfect thanks, will try this out now!