Limited External Calling when using Lync server to make external calls
Microsoft Lync Server, Cisco Firewall
One of my clients is running a Lync 2010 Server but recently he and others started to get this message which keeps popping up randomly every now and then. The message says:
Some calls to and from people outside of your corporate network may not connect due to a server connectivity problem. Try signing out and signing back. If the problem continues call your support team.
When the users hovers with his mouse over the Lync icon on the task bar it says: Limited External Calling.
The company has three Lync Servers 1- Edge 2- Mediation Server 3- Monitoring and Archiving.
All running Windows Server 2008.
What are the things that I need to look for? Is it a Lync Server issue or does it have something with the firewall open/closed ports etc. The firewall is Cisco but I am not sure what make. How do I get that?
Now my experience with Lync is very and I mean very limited if it ever exists so I will be extremely grateful if the answer is as simple and detailed please as it could be so I can fully understand and implement it.