diff --git a/labthings/server/exceptions.py b/labthings/server/exceptions.py
index de555f6a..464abdc5 100644
--- a/labthings/server/exceptions.py
+++ b/labthings/server/exceptions.py
@@ -1,4 +1,4 @@
-from flask import jsonify, escape
+from flask import escape
 from werkzeug.exceptions import default_exceptions
 from werkzeug.exceptions import HTTPException
 
@@ -31,7 +31,7 @@ def std_handler(self, error):
             or getattr(getattr(error, "__class__", None), "__name__", None)
             or None,
         }
-        return jsonify(response), status_code
+        return (response, status_code)
 
     def init_app(self, app):
         self.app = app