No sound notification ? Need help.

[panayotovip]

Now I use Ferdium version 6.4.0 installed from Flathub.
There is no sound notification.
My system is Debian 12 with KDE 5.27.5
In tray appear only red dot, if have some notifications.
But no make sound when notifications appears.
I guess some component must be allowed to access the system through Flatseal.
Also the cursor is not the same as the system cursor, but that's not too much of a problem.
It's more important that I start getting sound notifications somehow.
Help guys.
Any help will be appreciated.

ps: I forgot to mention that it is about gmail.
Sound notification does not appear for new mails in gmail.

[panayotovip]

It doesn't matter, it turned out that the notifications were stopped by the gmail account.