Go sdk failing to list clusters, gcloud cli succeeds

I am trying to run a very simple operation just to list the clusters in a project, using the google cloud sdk for go

package main

import (
    "context"
    "flag"
    "fmt"
    "log"
    "os"

    "google.golang.org/api/container/v1"
    _ "k8s.io/client-go/plugin/pkg/client/auth/gcp" // register GCP auth provider
)

var fProjectId = flag.String("projectId", "", "specify a project id to examine")

func main() {
    flag.Parse()
    if *fProjectId == "" {
        log.Fatal("must specific -projectId")
    }
    ctx := context.TODO()

    svc, err := container.NewService(ctx)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    // Ask Google for a list of all kube clusters in the given project.
    _, err = svc.Projects.Zones.Clusters.List(*fProjectId, "-").Context(ctx).Do()
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
}

the code fails as follows

▶ go run main.go --projectId my-project-id
Get "https://container.googleapis.com/v1/projects/my-project-id/zones/-/clusters?alt=json&prettyPrint=false": oauth2: cannot fetch token: 400 Bad Request
Response: {
  "error": "invalid_grant",
  "error_description": "reauth related error (rapt_required)",
  "error_uri": "https://support.google.com/a/answer/9368756",
  "error_subtype": "rapt_required"
}
exit status 1

However the command

gcloud container clusters list

succeeds?

What might be the issue here?

The answer in the link is not very informative.

EDIT: The problem was solved once I run

gcloud auth application-default login

Why is this needed?