The workflow said success, and Slack got nothing

On a CRM project for a Nordic B2B SaaS, one n8n workflow finished green on every run. Its job was to tell the sales team in Slack when a reply needed action. The team saw nothing.

The cause was a filter. It let an event through only if the event carried a campaign field. The sample payloads I had tested with carried one. Real reply events do not.

I fixed the condition and replayed exactly the 3 events that had been lost. Then I changed the tests, which now run on real payloads and not on sample ones.

A run that ends without an error has only shown that nothing threw. When the output is meant to reach a person, the far end needs its own check.