Windows All video add-ons failing. Fresh 12.1 install. [solved]

A couple of weeks ago, all of my video add-ons began to fail. XBMC version was 12.0. I'd done a fair bit of xml fiddling to customise the default Confluence home menu. I didn't think this would be related, but I thought a fresh install would be a good starting point.

I installed 12.1 today (full profile wipe & fresh install), and started installing add-ons again. Sadly all of my video add-ons are still doing the same thing. (Worth noting that audio add-on Soundcloud is working fine). I also installed the Log Uploader to help me prepare this post - it failed too. Eep.

This log file is after attempting to run divingmule's Jtv plugin, also contains failure of Log Uploader: http://pastebin.com/fMvufy8n

After running NASA add-on: http://pastebin.com/Rsx4DMkD

Youtube: http://pastebin.com/cgYgvWgR

Strangely, Vimeo worked the first time (I played a random video from 'Staff Picks'). Now it will load that section fine, but will throw a video URL error when I select one: http://pastebin.com/PVMu0uhC

Any clues?

Network errors. Check your network settings, make sure you don't have proxy enabled if your not using one.

Thanks for the reply. I began to suspect as much when I noticed a few other apps outside XBMC unable to get online (such as media scrapers not connecting to imdb). Yet regular browsing works fine in Chrome. Windows update may have borked something, I'll look into it. (Proxy not enabled for the record.)

I'm having this exact problem..and I tried installing fresh on another Pc at work and same issue..no proxies are installed..not sure what else to check.

Solved it.

What didn't work: Rolling back three months of Windows updates. Disabling all AV and firewall. Disabling router firewall. Adding HTPC to DMZ in router.

The solution: Going into Windows internet options (via control panel), then LAN settings, and unchecking "use a proxy". I had previously confirmed there was no proxy in use in XBMC settings, but hadn't looked at Windows internet options. I have no idea why the option was selected, or how it changed.