Hey man, it was me who answered before, but I wasn´t sure, so I deleted it.
Check if my BP works for you:
Spawn the sound actor at your lvl, anywhere, and uncheck the automatic activation, as shown in this image.
With the sound actor selected, in your lvl blueprint, right mouse and create a reference for it, then, just create the setup below, and activate the audio component or desactivate it as you want.
In this BP, when the player is inside the Trigger BOX (The green one in the first image) the music starts playing, when the player leaves the trigger box, the sound stops.
PS: You can also drag from the audio component and type Play and Stop, instead of activate and desactivate
Hope it helps you!