Loudspeaker on phone calls/video chat doesn't work.

[AC Question]

My loudspeaker on my Nexus 6P doesn't seem to work. I still get audio from music and videos fine. Also normal phone calls aren't a problem.

I've tried a factory reset and a data cache wipe with no luck.

Have no idea how to solve this or what's happened. Hopefully someone here might know.

Thanks in advance