Slack Trigger does not receive events despite correct configuration

[Yusuke_Uenishi]

Hello, I am experiencing an issue where the Slack Trigger node is not receiving any events from Slack.

The channel list in the node parameters also shows the error: Could not load list / Your Slack credential is missing required Oauth Scopes.

This problem persists even though all settings appear to be correct according to the documentation. This happens with both the Test URL and the Production URL.

Here is a summary of all the troubleshooting steps I have already taken:

1. Slack App Configuration (New app created from scratch):

• Event Subscriptions:
  • Enable Events is On.
  • The n8n Webhook URL is entered in the Request URL and is Verified.
  • Subscribed to the message.channels bot event.
• OAuth & Permissions:
  • Added channels:history and channels:read to Bot Token Scopes.
  • The app has been reinstalled to the workspace after every change to scopes or events.
  • There is no pending request to reinstall the app.
• App Approval:
  • My account is a Workspace Admin.
  • I have explicitly Approved the custom app in the “Manage Apps” settings.

2. n8n Configuration:

• Credentials:
  • Created a new credential using the correct Bot User OAuth Token (xoxb-...) from the Slack App.
  • The credential connection test in n8n passes successfully.
  • I have also tried deleting and recreating the credential multiple times.
• Workflow & Bot:
  • The bot user has been successfully /invited to the target channel. I have confirmed it is in the member list.
  • I am following the correct testing procedure: running “Execute Workflow” in n8n and then posting a new message to the channel while n8n is “Listening…”.

3. Alternative Tests:

• I also attempted to use a generic Webhook node with Slack’s Outgoing Webhooks app. This also failed to receive any events.

Despite all these steps, the trigger does not fire. It seems to be a communication issue between Slack and my n8n instance that is beyond standard configuration.

Could you please help me investigate this?

[rahibbutt]

Hi @Yusuke_Uenishi

Have you tried authenticating “Slack Trigger” node with an API access token instead of OAuth2? Because this node isn’t supported to work with the OAuth2 authentication.

Or, you could try the simple “Slack” node with OAuth2 authentication that you did already, to see if that works for you?

As far as I know, here are the supported authentication methods:

• API access token:

  • Required for the Slack Trigger node.
  • Works with the Slack node, but not recommended.

• OAuth2:

  • Recommended method for the Slack node.
  • Doesn’t work with the Slack Trigger node.

You can also refer to the Slack Trigger node documentation:

Slack Trigger node documentation | n8n Docs

Hope this answers your question.