404 error means that there is no file there or it is unavailable.
Could you load any model from the absolute URL?
(You can use any model from library - The Meshes Library | Babylon.js Documentation)
An absolute URL contains the entire address from the protocol (HTTPS) to the domain name (www.example.com) and includes the location within your website in your folder system (/foldernameA or /foldernameB) names within the URL.
Here is the example of loading the model with the absolute URL - https://playground.babylonjs.com/#QCU8DJ#169
It should work in your case too (if the id is correct or blank) - see code below.
public createPlayerMesh(id: string) {
const mesh: any = SceneLoader.ImportMesh(
id,
'https://playground.babylonjs.com/scenes/Dude/',
'Dude.babylon',
this._scene
);
return mesh;
}