Why can't callers hear me on the loudspeaker while I can hear them?

[Windows Central Question]

Callers cannot hear me on loudspeaker while I can hear them.

I have a Lumina 930 - 6 months old. The loud speaker function worked up until about 3 weeks ago. I think it was after my last software update that the function stopped working.

 

[eReS]

I had the same problem - HW issue
One of the microphones stopped working.

 

[Mhairi McKenzie]

I'm the exact same on a device 7 months old. I've also noticed that the screen doesn't go dark anymore when in calls so I constantly hang up or put people on hold.

Ridiculously frustrating and I'll be contacting MS on twitter to question what is going on.