What does no financial compensation mean when wanting to do an acting job?

I was looking up NON-UNION acting roles and there was this one option that was a short film and it said the pay rate is NO PAY.I tried asking the people who owned the actorsaccess website what it means,do I get paid or not.They just responded that it’s “no financial compensation”. Can someone easily explain what this means and also will I get paid if I get a chance to book the role?