How can a Telegram bot check if a user has blocked the bot or not?

Question

Bots

The point is.
About 4000 people used my bot, I wanted to do a small mailing with my channel and from the site of articles (+ the command to send off and on - so that a person can disconnect from the mailing), if he does not need to.
I came across a 403 error, the bottom line is that I send it to people who have already blocked my bot. How do you know if he's blocked or not? After all, I want to send it to others, but it falls at the beginning.

Answer 1

If you get a 403 error, then it means blocked. Mark this user as inactive in the database and move on to the next user.
How to handle errors depends on your programming language.