JWT验证错误：无法从请求中解析令牌

Currently I'm developing Laravel 5.8 with using JWT Auth, everything running as well in Postman, but when I tried for testing on Browser, I got a lot of errors and one by one has been fixed. Now I'm get another error when I try to pass JSON Web Token by using Request. The token isn't provided correctly. After I do sign in process in :

public function signin(Request $request)
  {
    $this->validate($request, [
      'username' => 'required',
      'password' => 'required'
    ]);
    // grab credentials from the request
    $credentials = $request->only('username', 'password');
    try {

        // attempt to verify the credentials and create a token for the user
        if (! $token = JWTAuth::attempt($credentials)) {
            return response()->json([
              'error' => 'Invalid Credentials, username and password dismatches. Or username may not registered.',
              'status' => '401'
            ], 401);
        }
    } catch (JWTException $e) {
        // something went wrong whilst attempting to encode the token
        return response()->json(['error' => 'could_not_create_token'], 500);
    }
    return response()->json([
      'token'   => $token
    ]);
  }

The token generated successfully. But when I need the token to another controller, the token generated unsuccessfully, one of example is in this method :

  public function index(Request $request)
  {
    // this will set the token on the object
    JWTAuth::parseToken();
    // and you can continue to chain methods
    $user = JWTAuth::parseToken()->authenticate();
    $token = JWTAuth::getToken();
    die($token);
    try {
        if (! $user = JWTAuth::parseToken()->authenticate()) {
            return response()->json(['user_not_found'], 404);
        }
    } catch (Tymon\JWTAuth\Exceptions\TokenExpiredException $e) {
        return response()->json(['token_expired'], $e->getStatusCode());
    } catch (Tymon\JWTAuth\Exceptions\TokenInvalidException $e) {
        return response()->json(['token_invalid'], $e->getStatusCode());
    } catch (Tymon\JWTAuth\Exceptions\JWTException $e) {
        return response()->json(['token_absent'], $e->getStatusCode());
    }

Everytime I'd like to JWTAuth::parseToken(); I got this error :

The token could not be parsed from the request

So why this happen? And what should I do? Because In signin method, the token successfully generated, but in index I can't access the token. Thanks for your attention.

Token needs to be passed via Headers in each api request Header Name: Authorization Expected Value: Bearer --token-- (without the -- ofcourse)