This means that we do not have a contract for reduced rates with a doctor. We don't know exactly what an out-of-network doctor will charge you.
If you choose a doctor or other health care provider who is out of network, your health plan may pay some of that doctor's bill. But it will pay less than if you get care from a doctor in-network. You will pay more money if you decide to use a doctor that is not in-network.
Check your plan documents for more details.