diff --git a/homeassistant/components/fritz/strings.json b/homeassistant/components/fritz/strings.json
index 6be393cc636..54dc76e3c59 100644
--- a/homeassistant/components/fritz/strings.json
+++ b/homeassistant/components/fritz/strings.json
@@ -56,6 +56,7 @@
       "reconfigure_successful": "[%key:common::config_flow::abort::reconfigure_successful%]"
     },
     "error": {
+      "unknown_error": "[%key:common::config_flow::error::unknown%]",
       "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
       "upnp_not_configured": "Missing UPnP settings on device.",
       "already_in_progress": "[%key:common::config_flow::abort::already_in_progress%]",