> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/troubleshooting/slack-not-in-channel.md).

# Fix Slack not_in_channel and channel_not_found in Duaer

When the Slack node in Duaer fails with not_in_channel, your Slack app is not a member of that channel. Invite the app to the channel.
## Why Duaer shows these errors

- not_in_channel: the channel exists, but your Slack app (bot) is not a member and cannot post.
- channel_not_found: usually a private channel the app is not in, so it cannot see it; or the channel ID is wrong.

## Fix it in Duaer

1. In Slack, open the channel and send /invite @YourApp, or select Add apps under Integrations in channel details.
2. Back in Duaer, pick the channel again from the list in the [Slack](/build/slack.md) node and select Execute step.
3. To post to public channels without inviting each time, add the chat:write.public scope under OAuth & Permissions, reinstall the app, and reconnect the [Slack credential](/integrations/builtin/credentials/slack.md) in Duaer. Private channels still need an invite.
## Questions

### Can Duaer post to a private Slack channel?

Yes, after you invite your Slack app to that private channel so Duaer can see it.

### Why does Duaer still fail after I added a Slack scope?

New Slack scopes apply only after you reinstall the app; then reconnect the Slack credential in Duaer.

## Related

- [Send a Slack message in Duaer](https://doc.duaer.com/build/slack.md)
- [Set up Slack credentials in Duaer](https://doc.duaer.com/integrations/builtin/credentials/slack.md)
- [Fix Notion object_not_found in Duaer](https://doc.duaer.com/troubleshooting/notion-object-not-found.md)