Hello Prem Yenne.
I understand you cannot establish connection to kubernetes API Server.
This may be as a result of your cluster nodes not being able to connect to your cluster API server pod.
To resolve this,
Run a Netcat command to verify that your nodes can resolve the cluster's fully qualified domain name (FQDN):
nc -vz <cluster-fqdn> 443
In rare cases, the firewall's outbound IP address can be blocked if you've authorized IP addresses that are enabled on your cluster. In this scenario, you must add the outbound IP address of your firewall to the list of authorized IP ranges for the cluster.
Please let me know if you have further questions
You can mark it 'Accept Answer' if this helped.