Pod not started after sidecar injection


I am getting below error while trying to inject istio sidecar container manually to pod.

in kubectl get events , i can see below error

Error creating: admission webhook "sidecar-injector.istio.io" denied the request: template: inject:443: function "appendMultusNetwork" not defined

In kube api server logsbelow errors is observed

W0505 02:05:30.750732 1 dispatcher.go:142] rejected by webhook "validation.istio.io": &errors.StatusError{ErrStatus:v1.Status{TypeMeta:v1.TypeMeta{Kind:"", APIVersion:""}, ListMeta:v1.ListMeta{SelfLink:"", ResourceVersion:"", Continue:"", RemainingItemCount:(*int64)(nil)}, Status:"Failure", Message:"admission webhook \"validation.istio.io\" denied the request: configuration is invalid: gateway must have at least one server", Reason:"", Details:(*v1.StatusDetails)(nil), Code:400}}

Please let me know if any clue on how to resolve this error