As has been pointed out, there are a number of similar recent forum posts on this issue. In one of the others, a forum member suggested checking the hosts file:
When I opened up the hosts file with Notepad++ in administrator mode as suggested I found that there were many references to plex (e.g. my.plexapp.com) followed by the tag “#Added by VPN Bypass”. When I removed these from the hosts file and saved it, the problem was fixed. My server logged in again, and I was able to access my plex.tv account from a browser on the PMS Windows 10 computer.
A long time ago I used a script created by a forum member to assist me with issues with accessing my plex server remotely whilst using a vpn on my PMS. It was this one:
I assume that this wrote some rules into the host file which is now causing validation/verification issues with Plex. Strange that this has happened all of a sudden but very happy to have a fix now. Thanks to all who have provided help on this.
