- 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 login.microsoftonline.com.
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.
Note 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.
Article ID: 2769142 - Last Review: Dec 28, 2016 - Revision: 1