diff --git a/app/routing/middleware/SAMLRequest.middleware.js b/app/routing/middleware/SAMLRequest.middleware.js
index 4062308..f0db6b4 100644
--- a/app/routing/middleware/SAMLRequest.middleware.js
+++ b/app/routing/middleware/SAMLRequest.middleware.js
@@ -17,7 +17,7 @@ class SAMLRequestMiddleware extends Middleware {
                 // Verify that the issuer is known
                 const sp = await ServiceProvider.findOne({entity_id: data.issuer, active: true})
                 if (!sp)
-                    return res.error(401, new Error('Unable to continue. The SAML issuer is unknown.'))
+                    return res.error(401, 'Unable to continue. The SAML issuer is unknown.')
 
                 req.saml_request = {
                     relay_state: req.query.RelayState || req.body.RelayState,