Hey Lucas,
Did it work earlier, or is this the first time with that project?
I would think that the SoundBank path is not valid. So maybe try to look in the Wwise Settings and open the folder in your Finder and see whether there's actually any SoundBanks in that folder.
If not, go to Wwise and check the location of the generated SoundBanks.
Now if everything is where it should be, try to close Unity, delete the Library folder, delete the SoundBanks, generate new SoundBanks and open Unity again.
Let us know if it works!