Cannot spatialize MediaPlayer Sound

I am using a mediaplayer that plays both video and sound, and I’d like to mute the sound in certain areas, using triggerboxes.
Unfortunatelly it doesn’t work :
When I launch the game (in PIE), the sound plays, then it mutes when I enter the triggerbox, but when I move out the triggerbox, the sound stays muted instead of playing again.
I tried a lot of different configurations : sound cue, blueprint with audiocomponent, or sound mix, but every time, when I mute the sound one time, it is never played again.
I suppose is it related to the media player framework.
Does anyone know the solution for this?