Similar to Issue #95 , if the Windows installation is set to password-less login PmsService cannot connect/sign-in to Plex.
Tray error is "unable to connect please check settings"
This is easy to test by just removing the password requirement for Windows - you will get the connection error.
Re-implementing password sign-in will fix the issue.
With this error it essentially removes the use case for PmsService as you could just have password-less login and Plex Media Server launch at startup.