I have a kubernetes cluster with 1 master node and 2 worker nodes. I have installed flannel as network plugin. The coredns pods inside the worker node keeps on going to CrashLoopBackOff state and then to running state. does anyone know what could be the reason.

if YES, please helm me with the solution

logs:

E0820 08:27:52.824620       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:320: Failed to list *v1.Namespace: Get https://10.96.0.1:443/api/v1/namespaces?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout
E0820 08:27:52.824913       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:315: Failed to list *v1.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host
E0820 08:27:54.825587       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed to list *v1.Service: Get https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout
E0820 08:27:54.827941       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:320: Failed to list *v1.Namespace: Get https://10.96.0.1:443/api/v1/namespaces?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host
E0820 08:27:56.827227       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed to list *v1.Service: Get https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host
E0820 08:27:58.831233       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed to list *v1.Service: Get https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host
2018/08/20 08:27:59 [INFO] SIGTERM: Shutting down servers then terminating
E0820 08:28:00.839084       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:315: Failed to list *v1.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host
E0820 08:28:02.847262       1 reflector.go:205] github.com/coredns/coredns/plugin/kubernetes/controller.go:320: Failed to list *v1.Namespace: Get https://10.96.0.1:443/api/v1/namespaces?limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: no route to host