That's interesting.
What was blocking Audacity from accessing the file? (Where / how did you give Audacity file access?)
That's interesting.
Perhaps also worth trying a newer Audacity version. Audacity 3.0.0 is now available: https://www.audacityteam.org/download/mac/
Earlier versions of Audacity also do that.
To do that you need to "mix stereo to mono". See: https://manual.audacityteam.org/man/tra ... u_mix.html
Unfortunately we can't answer that, it depends on Outlook. If they were really on the ball they would have cleared it already, but obviously they haven't.