Slack Trigger Crashes After Bot Mention — No Output and Cannot Stop Listening

Hi team, this is my first time opening a new topic!

I’m currently trying to set up a Slack Trigger in n8n to monitor a specific channel. The goal is for the workflow to run when the bot is mentioned in that channel.

However, I’m running into the following issue:

  • When I click “Execute Node” , it enters listening mode as expected.
  • After I mention the bot in Slack, the status briefly changes to “Pull in events from Slack,” but no output is shown , and the event is not processed .
  • From that point on, the UI becomes unresponsive:
    • Clicking “Stop Listening” does nothing.
    • I have to manually refresh the page to reset the state.

I’ve verified that:

  • The webhook URL is correctly set and publicly accessible.
  • Event Subscriptions in Slack are verified and app_mention is being sent.
  • All required OAuth scopes are in place.
  • The bot is in the correct channel and is being properly mentioned.



It will only run once when you use the test node option, what happens if you enable the workflow instead and use the production url in slack does that work better?

Even though the trigger successfully catches messages from Slack (e.g., app_mention), the workflow doesn’t proceed — instead, executions keep piling up in the Executions tab and repeatedly show as pending before being automatically marked as cancelled.