LIbgdx - Why is AssetManager not working?

I have tried to use Asset Manager to load some assets. Everything works fine, except for one part. Here is my code

My AssetHandler Class (contains assetManager)

public class AssetHandler {
    public static AssetManager manager;

    public static String wallFile = "3d/wall.g3db";
    public static String floorFile = "3d/floor.g3db";
    public static String stairsFile = "3d/stairs.g3db";
    public static String characterFile = "3d/character.g3db";

    public static void load() {
        manager = new AssetManager();

        manager.load(wallFile, Model.class);
        manager.load(floorFile, Model.class);
        manager.load(stairsFile, Model.class);
        manager.load(characterFile, Model.class);

    }

    public static void dispose() {
        manager.clear();
        manager.dispose();
    }

    public static void dispose(String fileName) {
        manager.unload(fileName);
    }

}

when I attempt to use the file, I wrote:

 model = AssetHandler.manager.get(AssetHandler.characterFile, Model.class);
 model = AssetHandler.manager.get(AssetHandler.wallFile, Model.class);

everything works but character file doesn't Other files do, but just this one file don't

Please Help I don't get why No errors/ exceptions poped up

Solution:

Add

manager.finishLoading();

at the end of load method.

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If you want to do it asynchronously, you should use manager.update() in render loop.

Refer to this for more information.

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Try to avoid public fields and static methods. (Not related to the question).