Lync 2013 or Lync 2010 can't connect to the Skype for Business Online service because a proxy is blocking connections from MSOIDSVC.exe


You may experience the following issues in Lync:

  • Lync 2013 or Lync 2010 can't connect to the Skype for Business Online (formerly Lync Online) service through a proxy that is configured by using a file://-based Proxy Auto-Configuration (PAC) file.

  • You can't connect to the Skype for Business Online service when you're using Lync 2013 or Lync 2010. When you view Network Monitor, traces show multiple TCP SYNC requests for

    Screen shot of network monitor, showing multiple T C P sync request for


To resolve this issue, use one of the following methods, as appropriate for your situation.

Method 1 (for end-users): Change the proxy settings in Internet Explorer

To resolve this issue, take one of the following actions in Internet Explorer:

  • Click to select the Use automatic configuration script option, and then configure an HTTP-based proxy PAC file.
  • Click to select the Automatically Detect Settings option, and then deploy Web Proxy Auto-Discovery (WPAD).

To do this, follow these steps:

  1. Start Internet Explorer.

  2. Click Tools, and then click Internet options.

  3. Click the Connections tab, and then click LAN Settings.

  4. In the Local Area Network (LAN) Settingsdialog box, click to select either Automatically Detect Settings or Use automatic configuration script, depending on your network configuration.

    For more information about how to configure an HTTP-based proxy PAC file, go to the following Microsoft website: Automatic Detection and Configuration of Browser Settings

    For more information about how to deploy WPAD, go to the following Microsoft website: Configuring Web proxy clients to automatically detect a Forefront TMG server

  5. Click OK, and then click OK again.

Method 2 (for admins): Create an application entry for Msoidsvc.exe in TMG

To resolve this issue for Microsoft Forefront Threat Management Gateway (TMG), create an application entry for Msoidsvc.exe. To do this, follow these steps:

  1. In the left pane, click Networking.

  2. Click the Network tab. Under the Tasks tab in the right pane, click Configure Forefront TMG Client Settings.

  3. In the Forefront TMG Client Settings dialog box, click New.

  4. In the Application Entry Setting dialog box, configure the following rules:

    Application Key Value
    msoidsvc Disable 0
    msoidsvc DisableEx 0


The same application settings can be applied to other firewalls. Additionally, your firewall server may require a firewall client to be installed on the end-user's computer.

More Information

This issue occurs when the Microsoft Online Services Sign In Assistant traffic doesn't go through the TMG firewall client, and a direct connection is attempted.

For example, this issue may occur in a scenario where all the following conditions are true:

  • Proxy Server Automatic Discovery isn't enabled.

  • A proxy server isn't configured in Internet Explorer.

  • The Automatically detect settings option isn't enabled in Internet Explorer.


    The only location that the Lync and Skype for Business clients use to detect network proxy configuration information is in the LAN settings option on the Connections tab in Internet options.

For more information about the WinHTTP limitations of supporting a file-based proxy, see WinHTTP AutoProxy Support.

Still need help? Go to Microsoft Community.