diff --git a/addons/utm/models/ir_http.py b/addons/utm/models/ir_http.py
index ed12d6061d0..e85210cef2d 100644
--- a/addons/utm/models/ir_http.py
+++ b/addons/utm/models/ir_http.py
@@ -11,6 +11,8 @@ class IrHttp(models.AbstractModel):
 
     def _dispatch(self):
         response = super(IrHttp, self)._dispatch()
+        if isinstance(response, Exception):
+            return response
         for var, dummy, cook in request.env['utm.mixin'].tracking_fields():
             if var in request.params and request.httprequest.cookies.get(var) != request.params[var]:
                 response.set_cookie(cook, request.params[var], domain=self.get_utm_domain_cookies())