So I've seen a lot of people having the same problem as I used to have. The microphone would occasionally stop working until restart. I've looked at a lot of forum posts and found one solution that fixed the issue. You see, the phone comes with the OK Google on every screen feature turned on for some reason. Apparently, it somehow collides with the system in a way that completely disables the microphone. Turning this option off will fix this problem (a restart might be required though). Also, keep in mind that you bought a very decent phone for a very good price. I thought unreliability would be an obvious thing that a phone this good and cheap would be a little unreliable. But that's probably just me.
