Server Version#: Version 1.19.4.2893
Player Version#: Web Version 4.35.1
Here is the log entry that I believe is most relevant:
HTTP error requesting GET https://plex.tv/updater/packages/71254/file (60, SSL peer certificate or SSH remote key was not OK) (SSL certificate problem: unable to get local issuer certificate)
AutoUpdate: Had file for https://plex.tv/updater/packages/71254/file but sha1 sum mismatched
Solution (for anyone interested:) I use SSL Inspection on my firewall, and for whatever reason, it was barking at the SNI hostname downloads.plex.tv and aborting the download. So, I had to create an ‘ignore’ exception for ‘downloads.plex.tv’ and this fixed my issue.