Adobe Audition - Unable to export my file as MP3

[Latinx Therapy]

I have exported MP3 files before, but for some reason, last night my program stopped exporting my files. I  highlight the track I need, which is the one labeled as Host, then I go to File>Export>Multitrack Mixdown>Selected Clips. 

I am no longer getting the little circle that shows the progress/percentage when project is complete/exported. I am using High Sierra on a Macbook (early 2015), updated Adobe Audition, & restarted computer. 

I also copied and pasted the file to another track and exported, it saved but with no audio sound! It was not muted when I highlighted and exported. 1 hr and 14 seconds were just silent. 

I sent the raw file to myself so I could open on another computer that has Adobe Audition, but all the tracks were flatlined. 

What am I missing?

[SteveG_AudioMasters_]

Initially, check the Master channel status in the Audition mixer. If the fader is set to zero, or it's muted, then even though the tracks look fine and aren't muted, you still won't get an output.