Issues with K8 apiservice after reboot

After creating the k8 cluster ,I rebooted the CentOs 7 system after that whatever kubectl commands I enter I get the following error" The connection to the server 10.a.bcd.efg:6443 was refused -did you specify the host right?". I have tried restarting docker and k8 ,double checked firewall for port 6443 but nothing works.Looks like the kube apiserver.service is not present in the system.I tried installing thay through snapd but that also doesnt work.What could be issue with apiserver service not working.

Cluster information:

Kubernetes version:1.19.4
Cloud being used: bare metal
Installation method:
Host OS: CentOS 7
CNI and version:
CRI and version:

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Hello, @kvats
export the path of config file.

$ export KUBECONFIG=/root/.kube/config