I met this problems too, after some many times try, I finally gave up. Only be able to convert WRF file to WMV and then export the WMV file to some other formats like MP4 and AVI. Specifically, you can read this guide which share their opinion on thi...

Did you ever try going to the "settings" and choose "audio" to decide the audio output devices? Or update WebEx Recording Player to the newest update and try again.

It would be better if you guys could let me directly use webex editor to convert wrf to mp4. Now when trying converting to mp4 it asks me to type in a mysterious password that i cannot find.

No, I did not find any options in webex online meeting to hide your names and profiles.

You need to download a WebEx Recording Editor first and then go to its editing section on the upper left side and at last choose import insert recording.