Cannot connect to any online resource

Solution 1:

Try adding the following to devenv.exe.config (in Common7\IDE folder):

<configuration>
  <system.net>
    <settings>
      <servicePointManager expect100Continue="false" />
    </settings>
  </system.net>
</configuration>

This is a known issue with some proxy servers that will be addressed in a future release.

Solution 2:

The following worked for me, I got this from the blog entry listed below.

in the devenv.exe.config file, in the <system.net> section add:

<defaultProxy useDefaultCredentials="true" enabled="true">
    <proxy usesystemdefault="True" />
</defaultProxy>

reference: http://gurustop.net/blog/2010/08/10/visual-studio-2010-extension-manager-online-gallery-behind-internet-proxy/

Solution 3:

I had to do a bit of all the above to get mine working. My system.net settings:-

<system.net>
    <defaultProxy useDefaultCredentials="true" enabled="true">
        <proxy proxyaddress="http://your.proxyserver.ip:port"/>
    </defaultProxy>
    <settings>
        <ipv6 enabled="true"/>
        <servicePointManager expect100Continue="false" />
    </settings>
</system.net>

Solution 4:

In my case, Visual Studio refused to read the settings from internet explorer. I finally got it to work by explicitely giving the url to the proxy and setting the servicePointManager expect100Continue to false. To manually add the proxy address, the xml looks like this:

<defaultProxy>
    <proxy proxyaddress="http://your.proxyserver.ip:port"/>
</defaultProxy>