Can't access plex server

Set up a new installation.
Installed plex over the dashboard.

Followed these instructions to set up a tunnel.

Whenever I go to localhost:8888 I get only access to the web client and its settings. I can’t access the server or the server setting and the server isn’t found!!
On a side note: The first time I tried it, I clicked on the “home” icon and suddenly was in the plex server but couldn’t claim it. Then I refreshed the page and since then I’m stuck on the web client.

Restarting the server, plex or any other service doesn’t help.
I tried to SSH with root and with the quickbox user account.

What do?

EDIT: Reinstalled plex, now I can access the server and settings BUT when I launch the plex client on windows, it still can’t find the server. The web client on http://IP:31400/web works though

I think this post can solve your problem: