There was an unexpected error

Same here! I’ve got a server in a nvidia shield and seems that some broken configuration blocks me to access the dvr settings. I’ve found this:

While that’s not my specific case, seems that I’m getting an HTTP 404:

HTTP/2.0 (0.3s) 404 response from GET https://epg.provider.plex.tv/lineups/5cfe43ef084e78001e5226d3/channels?X-Plex-Api-Token=xxxxxxxxxxxxxxxxxxxx (reused)
downloadContainer: expected MediaContainer element, found Error