Slack trigger stops working

Questions
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1

Describe the problem/error/question

I have a Slack Trigger in n8n that reacts to new messages, mentions, and reactions in a specific channel. It worked reliably for months but stopped triggering ~2 days ago, consistently around 16:00–17:00.

  • No executions are logged in n8n or Datadog, and Slack messages that should trigger the workflow are clearly visible.
  • Nothing changed in the Slack app setup; event subscriptions are active and point to the correct workflow URL. Also no changes in the n8n flow.
  • A colleague experienced a similar issue and fixed it by removing the channel ID in the trigger, saving, then re-adding and saving again. This workaround is not sustainable as it stops triggering from 16/17 then again.

##Workflow (just the trigger)

Information on your n8n setup

  • n8n version: 1.78.1
  • database: PostgreSQL 14
  • EXECUTIONS_MODE: queue
  • Running n8n via: Docker in k8s
  • Operating System: Amazon Linux EKS 1.28.5-20240227
1 Like
2

Try reconfiguring the channel periodically. Delete and re-configure the Channel ID in the trigger, save, and reactivate it. Automate this with a small maintenance sub-workflow if it’s recurring.

Revalidate Webhooks in Slack. Go to Slack App → Event Subscriptions, and paste the Production Webhook URL of the active trigger again to force re-verification (challenge/response).

3

Delete and re-configure the Channel ID in the trigger, save, and reactivate.
This was a workaround for us.
Seems like it happened due to copy/pasted Slack triggers. Just make sure you use new Slack triggers with new workflows and all is good (so far). Now with all new triggers we are not seeing this behaviour anymore :slight_smile: thanks for your help!