Last night we wanted to watch a show on the NBC app. This was the first time for us. The app asked if we had a provider, we do, so I said yes. It then wanted me to go to nbc.com/roku to link my provider. That page does not exist. Now what?
For more information about that channel's authentication and functionality, you'll want to contact NBC support directly to inquire further. Many channels on Roku are developed and maintained by the channel provider themselves.