EKS HorizontalPodAutoscalers no working with memory metric

I have an eks cluster in the latest version (1.21). I am trying to use a HorizontalPodAutoscaler to scale with memory usage but there is no scaling happening.

Utilization is currently at 164% but the hpa is not scaling up.

I am using the following hpa config.

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: "xxx-service-autoscaler"
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: xxx-service
  minReplicas: 1
  maxReplicas: 3
  metrics:
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageUtilization: 100