Annoying banner

anyone can explain how to stop this banner, it appears every seconds

From the top of my head that type of banner appears when you change volume and some other underlying gnome settings daemon changes. Since there is no icon or text in the banner it is difficult to say what is the underlying issue.

Suggest openna terminal and run

 journalctl -f

This will follow the journal log … maybe you will see something regularly appearing when the banner appears.