Server Version#: 1.16.0.1226
Player Version#: 3.2.20-25990c77
I updated my Plex server a week ago. Went on vacation and accessed it every day until yesterday (6/24/19). The message I received was Server is Unavailable, received this message while using my Xbox One, ASUS Laptop (PC) or my Android Tablet. I access a computer at my house using Real VNC and logged into my WD MyCloudPR4100 NAS, was unable to configure/open the Plex Media Server, same error. Stopped Plex and manually updated it to the previoous server version 1.15.8.1198. Started Plex application on the NAS and successfuly accessed Plex Meia Server. Accessed the Plex Media server from my XboxOne, PC Laptop and Android Tablet sccessfully. Having Real VNC installed sure helped fixing the problem remotely.
Sign me - I am happy again.