При отправке файла ВК бот пишет "Вложение удалено", хотя остальные типы файлов отправляет без проблем Python

token = 'токен'


GROUP_ID = "айди группы"



import vk_api
from vk_api.bot_longpoll import VkBotLongPoll, VkBotEventType
from vk_api.utils import get_random_id
from vk_api.keyboard import VkKeyboard, VkKeyboardColor

from urllib.request import urlretrieve
import json
import requests

import ssl

from db import execute_mysql as ex

ssl._create_default_https_context = ssl._create_unverified_context

vk_session = vk_api.VkApi(token = token)
vk = vk_session.get_api()
longpoll = VkBotLongPoll(vk_session, GROUP_ID)

def get_id_topics(title):
    board = vk.board.getTopics(group_id=GROUP_ID)['items']
    for i in board:
        if i['title'] == title:
            return i['id']


for event in longpoll.listen():
    if event.type == VkBotEventType.MESSAGE_NEW and event.from_user:
        board = vk.board.getTopics(group_id=GROUP_ID)['items']
        if event.obj.message['text'] == 'start':
            id_vk = event.obj.message['from_id']
            keyboard = VkKeyboard()
            for i in board:
                keyboard.add_button(i['title'])
            vk.messages.send(peer_id=id_vk, group_id=GROUP_ID, random_id=get_random_id(), keyboard=keyboard.get_keyboard(), message='Выберите обсуждение')
        elif event.obj.message['text'] in (i['title'] for i in board):
            id_vk = event.obj.message['from_id']
            topic_id = (get_id_topics(event.obj.message['text']))
            items = vk.board.getComments(group_id=GROUP_ID, topic_id=topic_id)['items']
            for comment in items:
                message = comment['text']
                if 'attachments' in comment.keys():
                    attachments = comment['attachments']
                    media_url = []
                    for attach in attachments:
                        print(attach)

                        type = attach['type']
                        body = attach[type]
                        owner_id = body['owner_id']
                        media_id = body['id']
                        if 'access_key' in body.keys():
                            access_key = body['access_key']
                            media_url.append(f'{type}{owner_id}_{media_id}_{access_key}')
                        else:
                            media_url.append(f'{type}{owner_id}_{media_id}')
                        print(media_url)
                        print('----')
                    vk.messages.send(peer_id=id_vk, group_id=GROUP_ID, random_id=get_random_id(), message=message, attachment=','.join(media_url))
                else:
                    print(00000)
                    vk.messages.send(peer_id=id_vk, group_id=GROUP_ID, random_id=get_random_id(), message=message)

много что перепробовал, и при загрузке файла на сервер и тд всегда одно и тоже "Вложение удалено" в чём может быть проблема?