in past have been able to see multiple media servers in my Plex Pass account. Just tried setting up new Plex media server (v.8.1.4235) on new Win10 Creators system, login to Plex account and can only see 1 Media Server in a remote location (Theta) and not the latest new install. Have installed latest Plex Media Server on new computer but unable to configure the new server (i.e Sunrise) or scan for the media on that machine - expected to see several machine on account (Theta and Sunrise), but only see one (Theta)
Must be missing an obvious step as as multiple accessible media servers have been running for 3 years with out issue or need for reconfiguration.
Thx in advance for assistance
cheers
cal
Open the web browser on the machine where you did install the second plex server.
point it to https://plex.tv/web
Once there, sign your browser out of your plex account
https://support.plex.tv/hc/article_attachments/115013732828/mceclip3.png
Now start your newly install plex server
then call up the URL for the local web app http://127.0.0.1:32400/web or http://localhost:32400/web
finish the initial configuration
Avoid Microsoft Edge for the first setup
followed you directions above and made sure that the Plex Media Server was not running, then logged back out of account
called up localhost URL and logged back in using my Plex Pass account
was not offered option to finish installation - went immediately to Plex Cloud Media Server and showed the items in it
the other server Theta was also available, but the newly installed server (should be Sunrise) does not show
prior to your suggestions had removed, cleaned (ccleaner), rebooted and reinstalled the Plex server on Sunrise and opened the localhost - same results only Plex Cloud and Theta showed, no Sunrise
again, thx for your guidance but still perPLEXed! 
Could you decline the offer to sign in to your plex account and continue the setup anyway?
Otherwise try this procedure:
https://support.plex.tv/hc/en-us/articles/204281528-Why-am-I-locked-out-of-Server-Settings-and-how-do-I-get-in-
no option to sign in and continue setup in the current state
uninstalled server again again using the additional steps outlined in Plex TV support for Uninstalling Plex Media Server
https://support.plex.tv/hc/en-us/articles/201941078-Uninstall-Plex-Media-Server
deleted current_user reg keys and deleted a local app data as outined in article above
prior to reinstall, disabled Kaspersky AV - suspect this may have been the issue
rebooted, reinstalled and now have the options to setup Plex Media Server and can see the server along with the other 2 locations - problem solved, but still wondering why it happened in first place, but suspect Kaspersky AV - oh well, working now!!
Thx for your assistance … no longer perPLEXed!!
