return
		}
	} else {
		namespaceToServices := push.ServiceIndex.HostnameAndNamespace[host.Name(service)]
		var namespaces []string
		for k := range namespaceToServices {
			namespaces = append(namespaces, k)
		}
		// If namespace is omitted, return successfully if there is only one such host name in the service index.
		if len(namespaces) == 1 {
			svc := namespaceToServices[namespaces[0]]
			hostname = string(svc.Hostname)