I need background noise removed so I can here just the voices

I have a project in audition due in 2 days and this issue keeps happening where after awhile for whatever reason, adding new tracks in a multitrack session will be inaudible no matter what I do. It’ll be after I have a bunch of tracks and it’ll be out of nowhere and it has happened again. Last time I just cut my assignment short but I need to meet a minimum time for this assignment and I literally don’t know what to do

I’m a complete beginner at audition and this is for an intro to digital softwares class.

Itll happen even if I completely delete and redownload an audio, copy a working track from a previous segment, if I mute and unmute it, it doesn’t work. But I can hear it in the waveform settings and I can see audio levels change in the level area.

EDIT:
After some more research I fixed it by switching the output to my headphones instead of default on the affected tracks

Need help with just the human words pleas and get rid of the back ground noise