In my application, faces messages are not rendered on UI, not sure what is exactly causing this issue. In the server log I see this:
WARNING: FacesMessage(s) have been enqueued, but may not have been displayed.
What is the reason for such kind of situations?
Make sure that you have placed
<h:message for="...">or<h:messages>tag in your page, see also JSF 2 message and messages example