Why is authentication not saved in Laravel?

Question

Laravel

Authentication succeeds, but when I try to check whether he is authorized to use it or not, it returns false.
Authentication function:

public function login(Request $data) {
        $credentials = [
            'phone' => $data['phone'],
            'password' => $data['password'],
        ];

        if (Auth::attempt($credentials)) {
            return response()->json(array('token' => Auth::user()->token), 200);
        } else {
            return response()->json(['error' => 'Incorrect phone or password',], 404);
        }
    }