Since I'm soooo used to holds, I'll explain what this means (I did receive a lot of it the past 2 cycles lol)
Schools have decided that your application is not strong enough for an interview now, so they are putting you aside. They will review the incoming applications, which they will have boatloads of, and continue to invite more applicants for interview. In the end, if they need to interview more applicants, they will come back to the "hold" applicants and review them again for more invites.
I received a lot of holds the past few years, and in the end, all of them ended up rejecting me in February and March anyways. I know this is harsh, but if you're on hold, just forget about that school and start focusing on others since the likelihood is pretty slim; remember, these schools do get tons of competent applicants anyways