Basic question: Display a message with cbmessagebox

This is a basic question, but, I can’t figure out, what I’m doing wrong.

I am trying to display a message after saving a configuration. I was under the impression that it is enough to inject messageBox into the handler:
property name="messageBox" inject="messagebox@cbmessagebox";

and the use messageBox.info() in the handler function:
messageBox.info( translateResource( uri="cms:meilisearchControl.configuration.saved" ) );

But, the message won’t display. What am I missing, please?

Thank you in advance!

Are you rendering the admin/general/notifications view in your admin layout, and are there any JS errors in the browser console?