session login user id not working

After registering send the code via sms mobile.

After entering the code I get the error.

Illuminate\Auth\SessionGuard::login(): Argument #1 ($user) must be of type Illuminate\Contracts\Auth\Authenticatable, int given, called in C:\xampp\htdocs\projects\borujerd\selda\vendor\laravel\framework\src\Illuminate\Auth\AuthManager.php on line 340

public function verified(Request $request)
{
    $request->validate([
        'code' => 'required',
    ]);
    $user = User::query()->where('code', $request->input('code'))->where('mobile', $request->input('mobile'))->first();
    if($user){
        $user->approved = 1;
        $user->save();
        auth()->login($user->id);
        return redirect()->route('exhibitor');
    } else {
        return redirect()->back();
    }
}