Error from server: rpc error: code = Unknown desc = error when getting metric values no matching metrics found for sessionQueueSize

[katukna]

I was trying to implement autoscaling for chrome nodes on selenium-grid using Keda autoscaling (scaledObject). I was trying to scale based on sessionQueueSize using selenium-grid scaler. But scaling doesn't occur when sessionQueue increases to "1" on the UI.

scaledObject.yaml
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
namespace: selenium-grid
name: chrome-scale-deployment
labels:
deploymentName: selenium-node-chrome
spec:
minReplicaCount: 2
maxReplicaCount: 5
scaleTargetRef:
name: selenium-node-chrome
triggers:
- type: selenium-grid
metadata:
url: 'http://selenium-hub.selenium-grid.svc.cluster.local:4444/graphql'
browserName: 'chrome'
unsafeSsl : 'true'
activationThreshold: "1"

keda-operator logs:

When I ran the below command to troubleshoot. I found this error.

kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/selenium-grid/sessionQueueSize?labelSelector=scaledobject.keda.sh%2Fname%3Dchrome-scale-deployment"
Error from server: rpc error: code = Unknown desc = error when getting metric values no matching metrics found for sessionQueueSize