Symptoms
This issue occurs when a user joins a meeting that is created in a non-federated organization from the network of the user's organization. The user's organization does not have a direct IP/TCP connection route to the Edge infrastructure of the non-federated organization.
When this issue occurs, the user receives the following error message:
We couldn't connect to the presentation because of network issues.
Additionally, the user cannot start audio or video in a meeting in Lync 2013.
Cause
This issue occurs because Lync 2013 does not use a configured HTTP proxy server to connect to the Edge infrastructure of the non-federated organization. Instead, Lync 2013 tries to directly connect to the Edge infrastructure incorrectly.
Resolution
To resolve this issue, install the March 10, 2015 update for Lync 2013.
