RDS instances cannot be discovered

1. Open Add RDS Instances dashboard
2. Fiil in access key and secret access key
3. Click on "Discover"
   Result: Empty list. In JS-console:

   main.33032369a65ee89d3b29.bundle.js:101 ERROR TypeError: Cannot read property 'indexOf' of undefined
       at AddAwsComponent.webpackJsonp.../../../../../src/app/add-aws/add-aws.component.ts.AddAwsComponent.isEnabled (main.33032369a65ee89d3b29.bundle.js:349)
       at Object.updateDirectives (main.33032369a65ee89d3b29.bundle.js:101)
       at Object.debugUpdateDirectives [as updateDirectives] (vendor.116fe155f32ab900ae64.bundle.js:120632)
       at checkAndUpdateView (vendor.116fe155f32ab900ae64.bundle.js:119801)
       at callViewAction (vendor.116fe155f32ab900ae64.bundle.js:120151)
       at execEmbeddedViewsAction (vendor.116fe155f32ab900ae64.bundle.js:120109)
       at checkAndUpdateView (vendor.116fe155f32ab900ae64.bundle.js:119802)
       at callViewAction (vendor.116fe155f32ab900ae64.bundle.js:120151)
       at execEmbeddedViewsAction (vendor.116fe155f32ab900ae64.bundle.js:120109)
       at checkAndUpdateView (vendor.116fe155f32ab900ae64.bundle.js:119802)
   View_AddAwsComponent_5 @ main.33032369a65ee89d3b29.bundle.js:101
   main.33032369a65ee89d3b29.bundle.js:101 ERROR CONTEXT DebugContext_
   

Expected result: list of available RDS instances: