Red Hat OpenShift Container Platform 4.x UPI installation fails while adding the nodes due to invalid hostname

Issue

• OpenShift 4.x UPI installation fails while adding the nodes to the cluster with below error :

./openshift-install --dir=/root/ocp4/install_binary wait-for bootstrap-complete --log-level=debug
DEBUG OpenShift Installer 4.5.8
DEBUG Built from commit 0d5c871ce7d03f3d03ab4371dc39916a5415cf5c
INFO Waiting up to 20m0s for the Kubernetes API at https://api.example.redhat.com:6443...
INFO API v1.18.3+6c42de8 up
INFO Waiting up to 40m0s for bootstrapping to complete...
E0923 17:13:22.862102    3875 reflector.go:307] k8s.io/client-go/tools/watch/informerwatcher.go:146: Failed to watch *v1.ConfigMap: Get https://api.example.redhat.com:6443/api/v1/namespaces/kube-system/configmaps?allowWatchBookmarks=true&fieldSelector=metadata.name%3Dbootstrap&resourceVersion=3752&timeoutSeconds=316&watch=true: dial tcp 10.103.8.80:6443: connect: connection refused

• No nodes added to the cluster :

# oc get nodes
NAME                                         STATUS   ROLES    AGE   VERSION