No service graph data found but Node Graph is working fine

I am new to Graphana and this is my first post in the community.

I am not able to generate Service Graph. It is showing as below

My datasource is configured like below

Relevant sections from values.yaml is also updated like below

...
storage:
  trace:
    backend: s3
    s3:
      bucket: bucket-name
      endpoint: s3.amazonaws.com  
      region: us-east-2  
      insecure: false  

overrides:
  defaults:
    metrics_generator:
      processors: [service_graphs]  # Explicitly activate service_graphs

...

metricsGenerator:
  enabled: true

I am seeing the Node Graph in each trace but not the Service Graph. Can someone suggest what is going wrong?

Tempo 2.7.2 image

please go through Metrics-generator | Grafana Tempo documentation docs and make sure the following:

checkout this repo GitHub - grafana/intro-to-mltp: Introduction to Metrics, Logs, Traces and Profiles session companion code. as an reference demo setup.