If you have debug logging, upload the Plex Media Server.log and PMS Plugin Logs\com.plexapp.system.log
See
Reporting Issues with Plex Media Server and Plex media Server log files support pages
Use 'More Reply Options' button to get to the forum interface to attach log files
Also
Find out the local ip address of the Plex Media Server PC (Start / Run / CMD and type command ipconfig ) and then use that instead of 127.0.0.1 in the url in a browser
eg 192.168.0.5:32400/web
Also try localhost:32400/web
There have been problems seen where 3rd party security software or proxy software causes problem with access to 127.0.0.1
Start / Run / cmd and try
ping 127.0.0.1
and see what you get
Sorry to ask for so much .... can you also start an elevated cmd window:
Start / Run / cmd and when you see cmd.exe appear in the search results window, right click on it and select 'Run As Administrator'
In this window, type in command
netstat -a -b > %localappdata% etstat_2014-10-09.txt
This will take a while to complete
Upload this text file (%localappdata% etstat_2014-10-09.txt) to your post as well
and one more:
check Control Panel / Internet Options
Connection tab to confirm no proxy configured/in use
Advanced tab / Security / Enable Enhanced Protected Mode is off