Two passwords and the one for 127.0.0.1 has an invalid email address attached to it.

Hi When I was given a PlexPass lifetime as a gift I found I'd set up the server with a password I'd forgotten and an email address with a typo.
The typo email address is already taken so I can't change the password.
The server is working when accessed through the local 192.168.1.XX address which has the email and password on the plexpass and this forum but I can't access it at 127.0.0.1.
The email in the registry entry (I'm on Win10) is the working one.
Where is the password for the original server stored?