Alright, I figured it out if you’re having issues with SONIC Wall. As my admin was away for a week…
I used .NET reflector to change the base URL in DependencyManifest.cs, line 10 to https, instead of http.
If you don’t have access to .net reflector, here’s a download:
https://dl.dropboxusercontent.com/u/8658081/ShareX/2015/11/GitDependencies.exe
(Replace the one at \Engine\Binaries\DotNET)