telegram.error.BadRequest: Chat not found

[nghlt]

After installed python-telegram-bot, I ran a simple script as bellow:

from telegram import Bot
my_token = '534*******:AAF*************'
channel_id = -10016********

def push_message(msg, chat_id=channel_id) -> None:
    bot = Bot(my_token)
    bot.sendMessage(chat_id, msg)

push_message('Hello channel')

I got an error telegram.error.BadRequest: Chat not found
Someone please help me.
I checked the channel ID and I think it's correct. I copied the message link from the channel then got the channel ID from this URL.

[Bibo-Joshi]

Hi. Please double check that your bot is a member of that chat. Note that bots can only be members of a channel if they are admin in that channel. To double check the chat_id, you can also extract it from the updates that your bot gets from that chat.

[obarboza92]

Hi, you need to add "-" as prefix for your chat id, for example if chat id is 12345, you need to add -12345

[Nusab19]

@Bibo-Joshi
My bot is getting telegram.error.BadRequest: User not found in a group when used bot.getChatMember.
It has the right of sending messages in the chat.

1. It doesn't happen once in the blue moon. It is consistent.
2. It happens for all the users, I tried it out manually.
3. In other groups, it works fine. ( even when with just sending message right )
4. The group is a public supergroup

[Bibo-Joshi]

Please don't Tag people just to get attention.
Please also don't ask the same question in multiple places at the same time
https://t.me/pythontelegrambotgroup/737228

[Nusab19]

I thought this should be placed as an issue rather than just asking in Telegram. So, I sent it here so in future, someone with the same issue can find this

[Nusab19]

Please don't Tag people just to get attention.

You are one of the participants in this issue. That's the reason of me mentioning you.