The error could means a few issues:
For one, the exact error i faced in my last deployment was that we recently changed the public IP of the edge server.
Resolution:
- Changed external DNS records to point to new public IP of the Edge server
- Ensured that all required Firewall rules are in place and configured correctly.
- Checked any application filtering and proxy at your Firewall and network?
- Which ports you used for AV, SIP and Web conf? 1 public IP associated with 3 different ports?
- Did you have a correct "Persistent Routing" from Edge server's internal interface to your SFB client network(s)?
Tools to use to troubleshoot
- Install SFB Debugging tool on the Lync server, then go the the installation folder, and copy out " Snooper" yellow color icon to you desktop.
- Use Wireshark to see where exactly went wrong.
- And try again to simulate the issue,
- Open the Lync desktop client's log using Snooper tool.
C:\Users\user-name\AppData\Local\Microsoft\Office\16.0\Lync\Tracing\Lync-UccApi-0.UccApilog