spinnaker: Spinnaker not triggering pipeline when new image is released to Docker registry

Title We have a Kubernetes cluster running on Google Container Engine and we are trying to setup Spinnaker so it triggers pipeline and deployes new images to the cluster from Google Container Registry.

We followed this tutorial step by step and set up Spinnaker running in our cluster: https://www.spinnaker.io/setup/quickstart/halyard-gke/

Cloud Provider GCP, GKE

Environment 1.4.2 running on GKE 1.7.6

Feature Area Pipeline triggers

Description

Steps to Reproduce Follow the tutorial at https://www.spinnaker.io/setup/quickstart/halyard-gke/ and setup an Application with load balancer and pipeline with automated triggers for GCR.

Additional Details

We set up the pipeline with automated trigger for our Docker Registry. Here is the resulting JSON:

{
...
"triggers": [
    {
      "account": "my-eu-gcr-account",
      "application": "<my-app>",
      "enabled": true,
      "organization": "<my-organization>",
      "pipeline": null,
      "registry": "eu.gcr.io",
      "repository": "<repo-address>",
      "status": [],
      "tag": "latest",
      "type": "docker"
    }
  ],
  "updateTs": "1508228071955"
}

However, whenever new image appears in the registry, the pipeline is not triggered. Spinnaker is running in the same cluster and has all the credentials set (following the tutorial). I tried leaving the tag option blank as well.

Does anyone know what am I missing?