I'm having the same issue. Can't watch NFL Network. I have FuboTV, deleted and rescanned the channels. Here is the error message I get:
nfl media: 401 Unauthorized: Grant id=[399722305], permissions=[] insufficient for MediaObject mcpId=[US-511-IN-472759], authorization=[MVPD], permissions=[NFLN]
My DVR is on WD PR4100 Channels version 2021.05.26.1807
I checked for a Channels update and was told I am up to date.
I also stopped and restarted the Channels app as it had been running since the last update.
WD put out an OS update that I have not installed, should I do that?