se agrega relación faltante en modelo Album

app/Models/Album.php

@@ -4,6 +4,7 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class Album extends Model
 {
@@ -13,8 +14,13 @@ class Album extends Model
         return $this->belongsTo(Artista::class, 'ArtistId');
     }
 
+    public function tracks(): HasMany
+    {
+        return $this->hasMany(Track::class, 'AlbumId');
+    }
 
-    protected $fillable = ['AlbumId', 'Title'];
+
+    protected $fillable = ['AlbumId', 'Title', 'ArtistId'];
 
 
     protected $table = 'albums';  //Si la tabla no es la esperada, definimos la variable $table con el nombre correspondiente.