Issues with Linking account

I recently had to rebuild my Parents Plex Server on a QNAP box (I did name it the same as before). I did this while I was logged into the Plex via my ID. I have tried several times to unlink my account and link the server to my parents account but nothing seems to work. I have to log into their server with my ID and PW. If I try to log out of the Plex server and log in with their ID and PW it indicates that it can find any servers. I also have to log into my account on their Ipads and Iphones for them to see their server. I have tried logging out of all account and logging into their account but still no server can be found. It did offer me a four digit code to enter on the Plex.tv\link and I tried that but still no server.

Please help.

Thanks.

OK, since no one seems to know or understand my issue. Lets try this another way. HOW DO I UNLINK MY ACCOUNT FROM A SERVER??

You remove the server in Settings>Devices if it is associated with your account.

if you really want to just start it from scratch as far as who is signed in and such, find the Preferences.xml file and delete it. it contains the machine identifier that it makes a server unique and all that, ( database will remain intact if you created libraries already)

Thanks, I will try that this weekend.

Yes that worked. Removed server from the list of devise. Thank.