For some time after the reboot , I get "kubectle get node " reply, later after do not get reply

Dear All,
Good evening
I am relatively new to kubernetes, and this is my first post to the group
I have followed kubeadm installation, initiated the control panel by using

sudo kubeadm init
when I check " kubectl get nodes" , I do get reply

kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8-master NotReady control-plane 15d v1.27.3

but after some time, when I try I get “kubectl get nodes” I get error message
itsupport@k8-master:~$ kubectl get nodes

The connection to the server 10.115.129.150:6443 was refused - did you specify the right host or port?

May be the service got crashed, wanted to check the log files for the reason , requesting which log files should I check
Guidance much appreciated

thanks
Joseph John

Cluster information:

Kubernetes version:
Client Version: v1.27.3
Kustomize Version: v5.0.1
Server Version: v1.27.3
Kustomize Version: v5.0.1
Cloud being used: bare metal
Installation method: dep based install
Host OS: Ubuntu 22.04
CNI and version:
CRI and version:

Dear All,
Good morning
I have this doubt, is it because of my repository mismatch this issues is happenining
my repo for kubernetees is

cat /etc/apt/sources.list.d/archive_uri-http_apt_kubernetes_io_-jammy.list
deb http://apt.kubernetes.io/ kubernetes-xenial main

my host is Ubuntu 22.04 ( jammy ) and in my repo it is pointing towarrds xenial (Ubuntu 16.04) , would this be the reason for the crashing of my services
Thanks
Joseph John

Thanks to the forum archive, I searched and I got the link

I changed as per the docs, restarted the services and waiting for the result
will update to the group
thanks