I just noticed this, probably because I haven’t used the DVR much lately - but the program guide only extends out 4 days. I seem to remember early on that it was out for much longer. When I try to refresh, it gets to 42%, 46, 60 or 72% and then stops.
Issue with the EPG provider, Plex is working with them to get it resolved.
There was an issue giving rise to JSON Parse Error where the response for the guide refresh contained error 403 Forbidden. This should be fixed now.
Additionally Plex Media Server beta 1.14.0.5465 has retries for failed requests to fetch the guide - so that in itself would have helped whilst the issue was there
Please do manual update to the guide and once that completes ok, then incremental updates would ensure the guide remains up to date
If problems persist, please provide fresh logs from the server with debug logging enabled beforehand and also a zip of the Diagnostics directory which is within the Plex Media Server data area
https://support.plex.tv/articles/201643703-reporting-issues-with-plex-media-server/
https://support.plex.tv/articles/200250417-plex-media-server-log-files/
https://support.plex.tv/articles/202915258-where-is-the-plex-media-server-data-directory-located/