At a quick glance, it looks like an authorization issue. Perhaps the token is misconfigured or has been removed or expired? (Related: Set up Telegram integration using the discourse-chat-integration plugin)
Can you share a bit more detail about what the problem is from the user perspective?
What isn’t working properly? What actions are being taken? What did you expect to happen that is not happening?
Were things working before and stopped working? Or are you just trying to set things up now and having a problem?