No sound output from mozilla firefox

Im using Manjaro linux arm MATE on raspberry pi 4b
I have found that the in-system sound-test available in sound preferences work perfectly. But no audio output is being received from mozilla
any help?

With Plasma you can use the sound app (speaker icon) to mute individual apps. Does MATE have something like that? When I first got Manjaro FF was muted.

I think mate doesn’t, i have checked all the option in the sound and preferences.