LFD259 LAB worker not able to connect with master node in Kubernetes

i am not able to connect worker node to master node

getting the error below:

ubuntu@ip-172-31-88-44:~$ sudo kubeadm join 172.31.92.198:6443 --token 7i3xij.1pf0136a6r3xkizr --discovery-token-ca-cert-hash sha256:32bf354f01be488b30ec583ae4d608ca0b238a55ef4778d5c2e3399a3621bb21
[preflight] Running pre-flight checks

error execution phase preflight: couldn't validate the identity of the API Server: Get "https://172.31.92.198:6443/api/v1/namespaces/kube-public/configmaps/cluster-info?timeout=10s": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
To see the stack trace of this error execute with --v=5 or higher

Master config:
kubectl config view
apiVersion: v1
clusters:

cluster:
certificate-authority-data: DATA+OMITTED
server: https://172.31.92.198:6443
name: kubernetes
contexts:

context:
cluster: kubernetes
user: kubernetes-admin
name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:

name: kubernetes-admin
user:
client-certificate-data: DATA+OMITTED
client-key-data: DATA+OMITTED

But on. worker node i am getting this error ::

ubuntu@ip-172-31-88-44:~$ kubectl get nodes
E0110 05:52:47.493279 14982 memcache.go:265] couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp 127.0.0.1:8080: connect: connection refused
E0110 05:52:47.493641 14982 memcache.go:265] couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp 127.0.0.1:8080: connect: connection refused
E0110 05:52:47.495078 14982 memcache.go:265] couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp 127.0.0.1:8080: connect: connection refused
E0110 05:52:47.495417 14982 memcache.go:265] couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp 127.0.0.1:8080: connect: connection refused
E0110 05:52:47.496871 14982 memcache.go:265] couldn't get current server API group list: Get "http://localhost:8080/api?timeout=32s": dial tcp 127.0.0.1:8080: connect: connection refused
The connection to the server localhost:8080 was refused - did you specify the right host or port?