Ошибка Slack Bot not_in_channel
"slack bot error not_in_channel"
This error arises when you are using the bot oauth token and the bot is not invited to the channel. To solve this you need to
Invite the bot(slack app) to join the channel.
Use the OAuth Access Token instead
To add Bot to your channel you need to write /invite @Bot_name in the slack channel
FishBrawler