diff --git a/providers/fab/src/airflow/providers/fab/www/extensions/init_appbuilder.py b/providers/fab/src/airflow/providers/fab/www/extensions/init_appbuilder.py
index 4662e50a439b4..7a6d8c6d8949d 100644
--- a/providers/fab/src/airflow/providers/fab/www/extensions/init_appbuilder.py
+++ b/providers/fab/src/airflow/providers/fab/www/extensions/init_appbuilder.py
@@ -165,6 +165,8 @@ def init_app(self, app, session):
         :param app:
         :param session: The SQLAlchemy session
         """
+        from airflow.providers.fab.www.utils import get_fab_auth_manager
+
         log.info("Initializing AppBuilder")
         app.config.setdefault("APP_NAME", "F.A.B.")
         app.config.setdefault("APP_THEME", "")
@@ -193,10 +195,12 @@ def init_app(self, app, session):
             self.menu = dynamic_class_import(_menu)
         else:
             self.menu = self.menu or Menu()
-
         self._addon_managers = app.config["ADDON_MANAGERS"]
         self.session = session
-        auth_manager = create_auth_manager()
+        try:
+            auth_manager = get_fab_auth_manager()
+        except RuntimeError:
+            auth_manager = create_auth_manager()
         with _init_app_lock:
             auth_manager.appbuilder = self
             # Invalidate cached security_manager so it binds to the current Flask app.