That makes it sound like there may have been an error in the claim process. One of the forum moderators wrote up some instructions for Windows users for the process to correctly reclaim the server:
Another option would be to just start completely over by following the directions here. There’s warning in red at the top of the article (you will lose all metadata in existing libraries, i.e., it will be like PMS was never installed):
https://support.plex.tv/articles/201941078-uninstall-plex-media-server/
