diff --git a/homeassistant/components/deconz/diagnostics.py b/homeassistant/components/deconz/diagnostics.py
index d8fdfeae2bd..11854421512 100644
--- a/homeassistant/components/deconz/diagnostics.py
+++ b/homeassistant/components/deconz/diagnostics.py
@@ -25,7 +25,9 @@ async def async_get_config_entry_diagnostics(
     diag["deconz_config"] = async_redact_data(
         gateway.api.config.raw, REDACT_DECONZ_CONFIG
     )
-    diag["websocket_state"] = gateway.api.websocket.state
+    diag["websocket_state"] = (
+        gateway.api.websocket.state if gateway.api.websocket else "Unknown"
+    )
     diag["deconz_ids"] = gateway.deconz_ids
     diag["entities"] = gateway.entities
     diag["events"] = {