External Mic Issues Causing Recording Failures: Seeking Solutions

App is pretty broken for me, at least with external Mic, despite changing it to internal or external explicitly. It will start recording and then 10-20 seconds into it, the waves will go flat, and it will no longer record NOR will it stop, just waves go flat. I think hit the stop button and it shows it cut off like 10 seconds before I saw the waves go flat. The product is borderline unusable in this state, and have no idea how to get it working again. I don't seem to have this issue in recent memory when I'm not at my desktop and only have the Macbook Mic, but using external mics despite me EXPLICITLY picking the Macbook Mic to keep it simple, seems to freak it out and END the recording early. Any fixes?