diff --git a/canaille/__init__.py b/canaille/__init__.py
index f12644ce..cf8f3088 100644
--- a/canaille/__init__.py
+++ b/canaille/__init__.py
@@ -1,4 +1,5 @@
 import datetime
+import sys
 from logging.config import dictConfig
 from logging.config import fileConfig
 
@@ -131,7 +132,8 @@ def create_app(config=None, validate=True, backend=None):
 
     app = Flask(__name__)
     with app.app_context():
-        setup_config(app, config, validate)
+        if not setup_config(app, config, validate):  # pragma: no cover
+            sys.exit(1)
 
     sentry_sdk = setup_sentry(app)
     try:
diff --git a/canaille/app/configuration.py b/canaille/app/configuration.py
index 7c52e5e6..2111e598 100644
--- a/canaille/app/configuration.py
+++ b/canaille/app/configuration.py
@@ -5,6 +5,7 @@
 from typing import Optional
 
 from flask import current_app
+from pydantic import ValidationError
 from pydantic import create_model
 from pydantic_settings import BaseSettings
 from pydantic_settings import SettingsConfigDict
@@ -63,7 +64,7 @@ def settings_factory(config):
     """Overly complicated function that pushes the backend specific
     configuration into CoreSettings, in the purpose break dependency against
     backends libraries like python-ldap or sqlalchemy."""
-    attributes = {"CANAILLE": (Optional[CoreSettings], None)}
+    attributes = {"CANAILLE": (CoreSettings, CoreSettings())}
 
     if "CANAILLE_SQL" in config or any(
         var.startswith("CANAILLE_SQL__") for var in os.environ
@@ -128,7 +129,12 @@ def setup_config(app, config=None, test_config=True):
     if not config and "CONFIG" in os.environ:
         config = toml_content(os.environ.get("CONFIG"))
 
-    config_obj = settings_factory(config)
+    try:
+        config_obj = settings_factory(config or {})
+    except ValidationError as exc:  # pragma: no cover
+        app.logger.critical(str(exc))
+        return False
+
     app.config.from_mapping(config_obj.model_dump())
 
     if app.debug:
@@ -137,6 +143,8 @@ def setup_config(app, config=None, test_config=True):
     if test_config:
         validate(app.config)
 
+    return True
+
 
 def validate(config, validate_remote=False):
     validate_keypair(config.get("CANAILLE_OIDC"))