Plex can't connect to server

[bit]

So I'm running into a new issue just recently where the other use on my local PC can't access the local plex server.

Some things to note:
 

• Plex was installed on my main account with admin blah blah like normal, I can run plex on that and it detects the "server" fine and can see the movies (the server is just the same pc i'm checking on, there's nothing going over the network here at any point, it's all the same PC)
• The other PC account with admin I made for my parents that's just "click this and account logs in and starts plex automatically" can't access it anymore. Just says it's unavailable. Running up to date plex, tried a regedit thing I found on the plex forums that said would fix it but didn't. 
   

No idea why this is happening, it used to be fine until I don't know when, I just noticed it when checking right now. Anyone have any idea what's going on? Tried running plex as admin on other pc account and the regedit thing and nothing. Plex doesn't seem to have any other answers aside from "check your router/ports" etc.