diff --git a/public/app/services/backendSrv.js b/public/app/services/backendSrv.js
index 819ce9d938e..dcd922b886d 100644
--- a/public/app/services/backendSrv.js
+++ b/public/app/services/backendSrv.js
@@ -106,6 +106,11 @@ function (angular, _, config) {
           });
         }
 
+        // for Prometheus
+        if (!err.data.message && _.isString(err.data.error)) {
+          err.data.message = err.data.error;
+        }
+
         throw err;
       });
     };