All volumes - etc is off and set on vibrator but Facebook volume is not, how to turn it off?

[powchutu]

Under Setting:

I set my sound:
"sound mode" to vibrate,

volume:
"ringtone, music, video, games and other media, notifications and systems" OFF

"vibration intensity": ON

"ringtones": SILENT

and everything below is unchecked except "vibration's" on.

Then Accessibility:
"hearing flash notification" and "turn off all sounds" is checked

others below is unchecked.

So how do you turn Facebook volume off?

Thank you so much!

 

[UJ95x]

Open Facebook. Go to settings and turn off sounds

 

[powchutu]

thank you!