Troubleshooting connections to TFS

In my current and previous lives, one of the problems I get involved in is when people can’t connect to Team Foundation Server for some reason.

Usually the following occurs:

  • “It was working yesterday but not today”
  • “I haven’t changed anything”
  • "Team Foundation Server tfsserver does not exist or is not accessible at this time."
  • I get an error message: TF31002: Unable to connect to this Team Foundation Server

TF31002: Unable to connect to this Team Foundation Server

The very first thing I do is confirm that it works for a known-good configuration – usually my workstation.

Providing that works and the server appears to be functioning, the next thing I do is ask the user to call the CheckAuthentication web service using Internet Explorer.

The URL for this is: http://TFSSERVER:8080/services/v1.0/ServerStatus.asmx?op=CheckAuthentication

By doing this check, I am doing four things:

  • Eliminating Team Explorer from the picture
  • Eliminating the .NET networking stack from the picture
  • Ensuring that Windows Authentication is working correctly (that’s why I say IE)
  • Ensuring that proxy settings are set correctly

In most cases I’ve seen, the TFS connection issues are because the proxy settings have changed or are incorrect. Because .NET and Visual Studio use the proxy settings from Internet Explorer, it’s important to have them set correctly.

In rare cases it’s beyond this. That’s when I start looking at things like:

  • Can I resolve the server name?
  • Can I connect using the IP address? Are there HOSTS file entries? (see: c:\windows\system32\drivers\etc\hosts)
  • Can I ping the server?
  • Can I telnet to port 8080?

After that I get stuck :) Enjoy your troubleshooting!

Update - I forgot these ones:

  • Does the user actually have access?
  • Run TfsSecurity.exe /server:servername /im n:DOMAIN\User to check their group memberships
  • Has the user changed their domain password lately?
  • In some cases they’ll need to logoff the workstation and log back on again to get a new security token.

Update #2:

  • Is the computer's domain certificate valid?
  • Running this command from the command prompt will update the certificate: gpupdate /force
Comments (16)
  1. The one that bites me the most is my domain password expiring. There is nothing that explicitly tells you that you password has expired. You just start getting access denied on everything.

  2. Check the Windows Event Log . Run TFS Best Practices Analyzer . (part of the Power Tools , requires PowerShell

  3. Roy L says:

    In my case the automatic configuration script worked in IE, but prevented VS from connecting to TFS. I had to add the BypassProxyOnLocal registrykey to get it to work (

  4. Add one more possible cause. The IE Tools>Options>Connections>AdvancedSettings for proxy is to be enabled to be able to hit the TFSServer site correctly. VS picks up the settings from the registry this sends to.

  5. NG says:

    We started seeing this error on some of our machines about 1 week after the TFS 2008 install. At this point, my computer can connect fine to TFS from VS (the TFS install was done using my local account on the server – we don’t use a domain/active directory). One of my colleagues is able to access the http://TFSSERVER:8080/services/v1.0/ServerStatus.asmx?op=CheckAuthentication link in IE while another can access this link via Firefox but not in IE. Neither of them can connect to TFS from VS 2008. We tried checking/unchecking proxy in IE’s LAN Setup but no luck yet.. I just installed TFS Server SP1 but the problem still remains.. any ideas?

  6. Ralph says:

    VS2010b2 on Vista versus Codeplex gave me a TF31002 saying "(404) Not found.". The solution originally provided in worked for the TF31002 error in my case. (Just my 2 cents..)

  7. ben dyer says:

    cool, I can’t telnet to port 8080. how do I fix that?

  8. Grant says:

    @Ben – Check the incoming firewall on the server and the outgoing firewall on your own machine.

    Try and connect from somebody elses machine.

  9. FT says:


    My connection with TFS was working last week but today I can´t connect my Server.

    I tried execute TfsSecurity.exe and receive this error:  "The signature is incorrect."

    What means this message ?

    How to fix ?


  10. Vikram says:

    Thanks doof.

    CheckAuthentication authentication service is running.

  11. Don Kedero says:

    I had the following error (ConfigurationSectionError on line 137) in Maching.Config. I removed the system.servicemodel-node and reinstalled WCF. This worked (also I didn't have a newsfeed in VS2008). Now I have and TFS works!

  12. Anand says:

    Great…I faced this problem. I am using my laptop in my office and I connect from my home thru VPN. VPN has apparantly changed the proxy settings and I was not able to connect to my TFS server from this morning. I changed the settings and it worked…

    Thank you.

  13. Arun says:

    @Grant: I have installed VS 2008 and Team Explorer 2008 in my machine(my machine is local and is not connected to LAN or any Network). I get the TF31005 Error. So I tried the steps you have mentioned above. But my IE does not display any page on entering the URL: http://TFSSERVER:8080/services/v1.0/ServerStatus.asmx?op=CheckAuthentication. So whats wrong with the TFS? Where is the Problem?

  14. Duke says:

    I tried to open Source Control on a TFS from SQL Server Mgmt. Studio 2012 and get this TF31002 error but I can connect to the same TFS 2012 from my VS 2012. May you lend me some helps here, thanks.

  15. Vivek Bansod says:


    When I click on Connect to TFS link from Visual Studio 2010, I am getting this error "Could not execute the following command Team.ConnecttoTeamFoundationServer"

    what could be the reason for this?

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