No one can hear me on my Galaxy Note 8 Edge! How do I fix? No one can hear me on my Samsung Galaxy Note 8 Edge when they call me or I call them.  I hear them clearly, but I have to race to turn the speaker on before they hang up.  How do I fix this problem when it seems my mic works fine when I use an app to record myself
Most apps use secondary source to capture audio when the primary source is down. The source switching is automatically done and, in a phone with good memory, might be seamless.

It is highly probable that your Mic (primary audio source) is down. When recording, the app might actually be switching over to secondary source for audio (which might be the loudspeaker). My advice is that you change the Mic of your phone.