ClusterIP service Not accessible from within the cluster pods - kubernetes

Question

I have got 2 deployments in my cluster UI and USER. Both of these are exposed by Cluster IP service. There is an ingress which makes both the services publicly accessible.
Now when I do "kubectl exec -it UI-POD -- /bin/sh" and then try to "ping USER-SERVICE-CLUSTER-IP:PORT" it doesn't work.
All I get is No packet returned i.e. a failure message.
Attaching my .yml file
apiVersion: apps/v1
kind: Deployment
metadata:
name: user-service-app
labels:
app: user-service-app
spec:
replicas: 1
selector:
matchLabels:
app: user-service-app
template:
metadata:
labels:
app: user-service-app
spec:
containers:
- name: user-service-app
image: <MY-IMAGE-URL>
imagePullPolicy: Always
ports:
- containerPort: 3000
livenessProbe:
httpGet:
path: /ping
port: 3000
readinessProbe:
httpGet:
path: /ping
port: 3000
---
apiVersion: "v1"
kind: "Service"
metadata:
name: "user-service-svc"
namespace: "default"
labels:
app: "user-service-app"
spec:
type: "ClusterIP"
selector:
app: "user-service-app"
ports:
- protocol: "TCP"
port: 80
targetPort: 3000
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: ui-service-app
labels:
app: ui-service-app
spec:
replicas: 1
selector:
matchLabels:
app: ui-service-app
template:
metadata:
labels:
app: ui-service-app
spec:
containers:
- name: ui-service-app
image: <MY-IMAGE-URL>
imagePullPolicy: Always
ports:
- containerPort: 3000
---
apiVersion: "v1"
kind: "Service"
metadata:
name: "ui-service-svc"
namespace: "default"
labels:
app: "ui-service-app"
spec:
type: "ClusterIP"
selector:
app: "ui-service-app"
ports:
- protocol: "TCP"
port: 80
targetPort: 3000
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: awesome-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
ingressClassName: nginx
defaultBackend:
service:
name: ui-service-svc
port:
number: 80
rules:
- http:
paths:
- path: /login
pathType: Prefix
backend:
service:
name: ui-service-svc
port:
number: 80
- path: /user(/|$)(.*)
pathType: Prefix
backend:
service:
name: user-service-svc
port:
number: 80

Answer 1

Ping operates by means of Internet Control Message Protocol (ICMP) packets. This is not what your service is serving. You can try curl USER-SERVICE-CLUSTER-IP/ping or curl http://user-service-svc/ping within your UI pod.