"Method [guard] does not exist - laravel

Question

Why does this error appears when the guard exists in auth.php
'guards' => [
'web' => [
'driver' => 'session',
'provider' => 'users',
],
'manager' => [
'driver' => 'jwt',
'provider' => 'managers',
],
'admin' => [
'driver' => 'jwt',
'provider' => 'admins',
],
],
And the providers also sets with right format. In the controller the register function is down below:
public function register(Request $request)
{
$validator = Validator::make($request->all(), [
'username' => 'required|string|max:255',
'password' => 'required|string|min:6',
]);
if ($validator->fails()) {
return response()->json($validator->errors(), 422);
}
$user = new Manager();
$user->username = $request->username;
$user->password = bcrypt($request->password);
$user->save();
$token = JWTAuth::guard('manager')->attempt($request->only('username', 'password'));
return response()->json(compact('user', 'token'));
}
The JWTMiddleware
<?php
namespace App\Http\Middleware;
use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;
class JWTAuth
{
public function handle($request, Closure $next, $guard)
{
try {
$user = JWTAuth::parseToken()->authenticate($guard);
if (!$user) {
throw new \Exception('User not found');
}
} catch (\Exception $e) {
return response()->json(['error' => 'Unauthorized'], 401);
}
return $next($request);
}
}
In kernel.php I have included these inside aliases array:
'jwt.manager' => \App\Http\Middleware\JWTManagerMiddleware::class,
'jwt.admin' => \App\Http\Middleware\JWTAdminMiddleware::class,
'jwt.auth' => \App\Http\Middleware\JWTAuth::class,
What am I doing wrong and how can I solve this?