Visual Studio TFS Server Not working 

Have you ever wondered how to resolve TFS Server not working correctly, please read till end to solve.

 As a developer, when you work on daily basis, there might be a chance you would have worked with Fiddler Tool to capture .Net request/response from server that was required to add default proxy to machine.config file 

Solution 
Remove the <system.net> tag from machine.config file and try connecting TFS Server. 

 Cheers !

In General Fiddler is the free version tool available online, and one of the tools is 
Fiddler - Free Web Debugging Proxy - Telerik

1. Download Fiddler https://www.telerik.com/download/fiddler
2. To trace incoming from .Net project required to add .net settings in machine config file
3. Now the question is how to do ?
4. Open notepad as Run as Administrator 
5. Notepad File menu click on open and paste this code %WinDir%\Microsoft.NET\Framework\v2.0.50727\CONFIG
6.  Choose the file type as all files 
7. Look for machine.config file
8. Open it
9. Add the following lines after </system.web>  tag and save 

Add the following XML block as a peer to the existing system.net element, replacing any existing default Proxy

element if present:
 <!-- The following section is to force use of Fiddler for all applications, including those running in service accounts -->
<system.net>
<defaultProxy
                enabled = "true"
                useDefaultCredentials = "true">
<proxy autoDetect="false" bypassonlocal="false" proxyaddress="http://127.0.0.1:8888" usesystemdefault="false" />
</defaultProxy>
</system.net>10. Now Start the Fiddler
11. Fiddler will capture all the requests from .Net