Plex - 502 Proxy Error (Can't access http://my_server_ip:31400/web/)

Just ran into a problem with Plex. When clicking on the Plex tab on my Quickbox dashboard, I arrive at the following notice instead of the Plex dashboard.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /web/.

Reason: Error reading from remote server

Apache/2.4.18 (Ubuntu) Server at [My Server IP] Port 31400

Whats weird though is that Plex seems to be running just fine as I can watch a movie on Plex via the [] interface that I have my servers plex connected to.

Even so, this still seems to be a problem, so I appreciate any help. thanks in advance!

Can you access http://my_server_ip:32400/web/

When I try that, I just get this screen:

The connection was reset

The connection to the server was reset while the page was loading.

The site could be temporarily unavailable or too busy. Try again in a few moments.
If you are unable to load any pages, check your computer’s network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

I’m a moron. Forgot I had it only set to https/ssl so I had to add https://. Sorry for the bother. Since were here, is there anyway to modify the Plex link in the dashboard so it uses https instead of http?

There is a solid method if you setup Plex as a subdomain.

Check this out:

Works like a charm. Thanks!