we have the following Servers in our infra.

Lync frontend

lync edge  and tmg

from last one week internal to external calling is not working , some strange issue

1- External to external voice calling is working.

2- internal to external chat is working,

but internal to external voice calling suddenly stops working from last week,

lync analyzer is showing all green , no issues, I really don't know whats the issue

any suggestions

Here are some items to check:

• Ensure that all of the services on the edge are started.
• Ensure that the edge is associated with the front end.
• Ensure the the edge's internal name is resolvable from all clients on your internal network.
• Ensure that the edge can route to all clients on your internal network through the internal interface and not the external.  This may involve adding persistent routes.
• Ensure that your clients have firewall access to the internal edge NIC on port TCP\443 and UDP\3478.
• Ensure that the public IP address of the A\V edge server is listed in the topology builder for the edge as well as the private address.
• Ensure that you're using bi-directional NAT for the A\V edge server.  Meaning that outbound traffic from that public IP looks like your NAT and not your firewall's IP.  Ensure the same for inbound traffic.
• Make sure that Tcp\443, UDP\3478, TCP\50000-59999, and UDP\50000-59999 are open in both directions from the AV IP to the Internet