Replace kusers links with discuss forum link (#10321)

content/en/docs/tasks/debug-application-cluster/debug-service.md

@@ -623,7 +623,7 @@ us know, so we can help investigate!
 
 Contact us on
 [Slack](/docs/troubleshooting/#slack) or
-[email](https://groups.google.com/forum/#!forum/kubernetes-users) or
+[Forum](https://discuss.kubernetes.io) or
 [GitHub](https://github.com/kubernetes/kubernetes).
 
 {{% /capture %}}

content/en/docs/tasks/debug-application-cluster/troubleshooting.md

@@ -84,9 +84,9 @@ these channels for localized support and info:
 - Spain: `#es-users`
 - Turkey: `#tr-users`, `#tr-events`
 
-### Mailing List
+### Forum
 
-The Kubernetes / Google Kubernetes Engine mailing list is [kubernetes-users@googlegroups.com](https://groups.google.com/forum/#!forum/kubernetes-users)
+The Kubernetes Official Forum [discuss.kubernetes.io](https://discuss.kubernetes.io)
 
 ### Bugs and Feature requests