Unifi widgets show warning with no data

public/locales/en/common.json

@@ -51,7 +51,8 @@
         "wlan_users": "WLAN Users",
         "up": "UP",
         "down": "DOWN",
-        "wait": "Please wait"
+        "wait": "Please wait",
+        "empty_data": "Subsystem status unknown"
     },
     "docker": {
         "rx": "RX",