The patient has insurance but once you have insurance you have to find healthcare professionals who accept your insurance, doctors don’t have to accept any insurance plan. The insurance company here has a list of health providers that accept their coverage (we call this in network) and you can go to them for care. The insurance company’s list is poorly maintained so many of the listed providers went out of business, stopped accepting the insurance plan, or stopped accepting new patients.
If you go to a doctor that is out of network, the insurance company charges you much much more for the visit if they cover it at all, or you may have to pay completely out of pocket.