Microphone won't work on S4, help!

[Rikku Watro]

My S4's stock voice recorder works, but apps like Smule Sing and StarMaker won't record my voice. it seems like my microphone isn't working except for in the stock voice recorder app

 

[Jenkittykat]

Same issue here, only with galaxy 7 edge. I found this one YouTube. She addresses it briefly at the end. If you scroll down to the comments, you'll see that it's a common issue.

https://youtu.be/Zw0ANeayDWA