diff --git a/hassio/api/proxy.py b/hassio/api/proxy.py
index f67a1adc5..424c4affa 100644
--- a/hassio/api/proxy.py
+++ b/hassio/api/proxy.py
@@ -153,7 +153,7 @@ class APIProxy(CoreSysAttributes):
 
         except (RuntimeError, ValueError, ClientConnectorError) as err:
             _LOGGER.error("Client error on WebSocket API %s.", err)
-        except HomeAssistantAuthError as err:
+        except HomeAssistantAuthError:
             _LOGGER.error("Failed authentication to Home Assistant WebSocket")
 
         raise APIError()
diff --git a/tox.ini b/tox.ini
index 23310edf9..16c09e69f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,7 @@ envlist = lint
 
 [testenv]
 deps =
-    flake8==3.5.0
+    flake8==3.6.0
     pylint==2.1.1
     -r{toxinidir}/requirements.txt