fix: warn on unknown server

See #581

pkg/app/app.go

@@ -426,7 +426,9 @@ func GetAppStatuses(apps []App, MachineReadable bool) (map[string]map[string]str
 	for server := range servers {
 		cl, err := client.New(server)
 		if err != nil {
-			return statuses, err
+			log.Warn(err)
+			ch <- stack.StackStatus{}
+			continue
 		}
 
 		go func(s string) {