Nobody can hear me, when switching to speaker while calling on external apps
Hello
I have a strange issue:
When I do phone calls on external apps (not the built-in ios calling app) like whatsapp, skype, imo, etc. and I switch to speaker mode or to video mode, nobody can hear me. They can see me but do not hear me. If I switch back to the normal calling mode, they start hearing me again.
If I call with the standard ios app and switch to speaker mode or even to FaceTime, there is no issue. Everything works well, they see me, they hear me, everything is fine.
I checked the privacy settings for my mic, and every app has access to it. None is disabled. I rebootet several times, I played with those buttons enabling and disabling the access multiple times, and I even did a complete reset (some months ago, ios 9.3.3 was the latest at this time) but still nothing helps.
Has anyone an idea, what the problem could be?!
Thanks in advance
iPhone 6s, iOS 9.3.3