Same issue here. After the password reset, my Plex server, access locally in my LAN, doesn’t show my previous libraries. Only the online one. Running it on the QNAP Nas.
Update:
With that I could solve the issue. Library is back there on the server, just had to login and logout on the server as well.
I am running Plex on QNAP. After resetting my password, my server got unlisted and I could not register it to my Plex account. I’ve tried several times to login from the local IP, but still could not see my libraries. I’ve even followed this article to delete the Preferences.xml file: