How to play converted mp3s in iTunes

Hi guys, I'm new to Screenflow 8, just purchased it, I have recorded my voice only through my external mic, I watched a tutorial on how to export audio only (simple), I converted it from a mp4 into mp3 within Screenflow, that was successful, it's stored on my computer as an mp3, but I can't open it with iTunes and play it, what do I need to do? Thanks. PS: I can't open and play it with Quicktime Player either. I have Mac OS High Sierra 10.13.6 and iTunes 12.8.1.2