diff --git a/src/firefly/application.py b/src/firefly/application.py
index cc38d23f..390528c3 100644
--- a/src/firefly/application.py
+++ b/src/firefly/application.py
@@ -21,7 +21,7 @@
 from haven import load_config
 from haven import load_instrument as load_haven_instrument
 from haven import registry
-from haven.exceptions import ComponentNotFound
+from haven.exceptions import ComponentNotFound, InvalidConfiguration
 from haven.instrument.device import titelize
 
 from .main_window import FireflyMainWindow, PlanMainWindow
@@ -540,8 +540,10 @@ def prepare_queue_client(self, client=None, api=None):
             try:
                 api = queueserver_api()
             except InvalidConfiguration:
-                log.error("Could not load queueserver API "
-                          "configuration from iconfig.toml file.")
+                log.error(
+                    "Could not load queueserver API "
+                    "configuration from iconfig.toml file."
+                )
                 return
         # Create the client object
         if client is None:
diff --git a/src/firefly/queue_client.py b/src/firefly/queue_client.py
index 4ba9ee32..0213b03d 100644
--- a/src/firefly/queue_client.py
+++ b/src/firefly/queue_client.py
@@ -9,7 +9,7 @@
 from qtpy.QtCore import QObject, QTimer, Signal
 
 from haven import load_config
-from haven.exceptions import UnknownDeviceConfiguration, InvalidConfiguration
+from haven.exceptions import InvalidConfiguration
 
 log = logging.getLogger()
 
@@ -18,7 +18,9 @@ def queueserver_api():
     try:
         config = load_config()["queueserver"]
     except KeyError:
-        raise InvalidConfiguration("Could not load queueserver info from iconfig.toml file.")
+        raise InvalidConfiguration(
+            "Could not load queueserver info from iconfig.toml file."
+        )
     ctrl_addr = f"tcp://{config['control_host']}:{config['control_port']}"
     info_addr = f"tcp://{config['info_host']}:{config['info_port']}"
     api = REManagerAPI(zmq_control_addr=ctrl_addr, zmq_info_addr=info_addr)
diff --git a/src/haven/exceptions.py b/src/haven/exceptions.py
index b1a7baac..0e05b443 100644
--- a/src/haven/exceptions.py
+++ b/src/haven/exceptions.py
@@ -16,7 +16,7 @@ class GainOverflow(RuntimeError):
 
     ...
 
-    
+
 class FileNotWritable(IOError):
     """Output file is available but does not have write intent."""
 
@@ -55,8 +55,10 @@ class IOCTimeout(RuntimeError):
 
 class InvalidConfiguration(ValueError):
     """The configuration files for Haven are missing keys."""
+
     ...
 
+
 class UnknownDeviceConfiguration(InvalidConfiguration):
     """The configuration for a device does not match the known options."""