Telegram bot initiate conversation with a user

Question

I am writing a Telegram bot, to simplify the issue let's say you can ask the bot questions in a channel and it replies to you in private. When the bot receives the command it takes the chat_id of the user from: update.message.from_user.id

But when I do this I get an error:

Unauthorized: Forbidden: bot can't initiate conversation with a user

This sounds quite logical, as I assume this prevents from writing spam bots. The question is how do I overcome it? How can I let the user enable private messages from the bot?

Note: The bot does succeed sending messages to me but not to other users.

Solution

Telegram Bots can't initiate a conversation with a user. Only an user can initiate it by clicking on the start button. There is no way to around this.

In your case, you can ask the user to start the bot before asking questions in the channel, for example by attaching a button containing the bot URL (https://t.me/bot_username).

Comments

[Pumych]

In that solution we are not sure that specific user pressed the button, right?

[MarcoBuster]

@Pumych when a user presses a button, you receive a CallbackQuery update / object; you can check the form field for checking which user clicked on the button. Anyway, if it's a URL button, you can't tell, but you can see who issued the /start command to your bot.