如何在电报中向新成员发送带有机器人的个人消息

Question

我有一个电报群，当人们加入时，我想给他们发消息。我不是指在群组中发布的消息，我指的是将通过机器人发送给该人的私人消息。我为此找到了一个示例代码，如下所示，但此代码仅适用于成员很少且我为试用目的而设置的组。它在我的 1k 成员组中不起作用。

import requests
import json
import time

BOT_API_KEY = 'xxxxxxxxxxxxxxxxxxx'


CHAT_ID = 'xxxxxxx'

def send_welcome_message(new_member):
    # Get the new member's name and ID.
    name = new_member['first_name']
    user_id = new_member['id']

    message = f"Hello {name}, Welcome to  Group. "

    # Send the message to the new member's private chat.
    url = f"https://api.telegram.org/bot{BOT_API_KEY}/sendmessage"
    data = {"chat_id": user_id, "text": message}
    response = requests.post(url, data=data)
    
    

def handle_updates(updates):
    for update in updates["result"]:
        if "message" in update and "new_chat_members" in update["message"]:
            # Get the list of new members.
            new_members = update["message"]["new_chat_members"]
            for new_member in new_members:
                # Send a welcome message for the new member.
                send_welcome_message(new_member)

def get_updates(offset=None):
    url = f"https://api.telegram.org/bot{BOT_API_KEY}/getupdates"
    params = {"timeout": 30, "offset": offset}
    response = requests.get(url, params=params)
    return json.loads(response.content)

def main():
    last_update_id = None
    while True:
        updates = get_updates(last_update_id)
        if len(updates["result"]) > 0:
            handle_updates(updates)
            last_update_id = updates["result"][-1]["update_id"] + 1

if __name__ == '__main__':
    main()

会是什么原因？