If you additionally grant them access to DVR, you also need to grant them access to a library of the type “tv show” and “movies” each.
Depending on whether you are allowing them access to Plex’s online streaming media, the media source for live TV is named differently:
“Live TV & DVR” under your own server
“Live TV” under the “Plex” server name at the bottom of the sidebar list.
Either way, you might have to pin the live tv media source to the sidebar for each user individually.
Please don’t post snippets of log files.
They are not helpful.
The error messages above have nothing to do with the issue at hand and can be safely ignored.