Unable to discover Plex Media Server, what am I doing wrong?

Installed PlexConnect as per this guide: https://github.com/iBaa/PlexConnect/wiki/Install-Guideand I can see the Plex interface when going into trailers.

 

However it won't discover my server, here is what the console shows when scanning for a server in settings in Plex:

20:16:03 DNSServer: DNS request received!
20:16:03 DNSServer: Source: ('192.168.1.24', 63334)
20:16:03 DNSServer: Domain: setup.icloud.com
20:16:03 DNSServer: ***forward request
20:16:04 DNSServer: -> DNS response from higher level
20:16:04 DNSServer: DNS request received!
20:16:04 DNSServer: Source: ('192.168.1.24', 65393)
20:16:04 DNSServer: Domain: appldnld.apple.com
20:16:04 DNSServer: ***restrain request
20:16:04 DNSServer: -> DNS response: 192.168.1.4
20:16:05 DNSServer: DNS request received!
20:16:05 DNSServer: Source: ('192.168.1.24', 58047)
20:16:05 DNSServer: Domain: apple.com
20:16:05 DNSServer: ***forward request
20:16:05 DNSServer: -> DNS response from higher level
20:16:40 DNSServer: DNS request received!
20:16:40 DNSServer: Source: ('192.168.1.24', 59955)
20:16:40 DNSServer: Domain: trailers.apple.com
20:16:40 DNSServer: ***intercept request
20:16:40 DNSServer: -> DNS response: 192.168.1.4
20:16:40 WebServer: serving .xml: /
20:16:40 PlexAPI: ***
20:16:40 PlexAPI: looking up Plex Media Server
20:16:40 PlexAPI: ***
20:16:41 PlexAPI: GDM: No servers discovered
20:16:43 PlexAPI: No Response from Plex Media Server
20:16:43 PlexAPI: We failed to reach a server. Reason: [Errno 10061] No connecti
on could be made because the target machine actively refused it
20:16:43 PlexAPI: Servers (local, plex.tv, MyPlex): 1
20:16:43 WebServer: serving .xml: /
20:17:03 DNSServer: DNS request received!
20:17:03 DNSServer: Source: ('192.168.1.24', 61957)
20:17:03 DNSServer: Domain: appldnld.apple.com
20:17:03 DNSServer: ***restrain request
20:17:03 DNSServer: -> DNS response: 192.168.1.4

My Plex server is on 192.168.1.4 and the Apple TV is 192.168.1.24.  I've tried turning off firewalls on the Plex server with no joy.  

 

I think I might have set Plex up originally to require authentication so local devices can't see the server/shares but I can't find a way to get it working.

 

I have PlexConnect 0.5-dev installed.  Please help?

 

Edit: If I enable GDM on the server, I can get through but if I disable GDM and edit Settings.cfg as detailed here: https://github.com/iBaa/PlexConnect/wiki/Settings-for-advanced-use-and-troubleshootingit won't go through and I get this error:

21:13:03 PlexAPI: No Response from Plex Media Server
21:13:03 PlexAPI: We failed to reach a server. Reason: Unauthorized
21:13:05 PlexAPI: No Response from Plex Media Server
21:13:05 PlexAPI: We failed to reach a server. Reason: [Errno 10061] No connecti
on could be made because the target machine actively refused it
21:13:05 PlexAPI: Servers (local, plex.tv, MyPlex): 1