diff --git a/homeassistant/components/tankerkoenig/strings.json b/homeassistant/components/tankerkoenig/strings.json
index 7017c6e5fed..29f4f439dd5 100644
--- a/homeassistant/components/tankerkoenig/strings.json
+++ b/homeassistant/components/tankerkoenig/strings.json
@@ -42,6 +42,9 @@
           "show_on_map": "Show stations on map"
         }
       }
+    },
+    "error": {
+      "invalid_auth": "[%key:common::config_flow::error::invalid_auth%]"
     }
   },
   "entity": {