Written by The Lync 2013 client shows the popup ‘Network password required to connect’ when started:
This can occur when you are using a proxy server. The Lync client tries to reach several internal and/or external domains depending on your configuration. Internal traffic must remain internal, so this will fail if send over the proxy.
Solution without federation
On several sites I found out you have to exclude the internal domains, which the Lync client uses, from your proxy settings by modifying the proxy script or adding them as exceptions in your proxy settings:
- lyncdiscoverinternal.yourdomain.com
- lyncdiscover.yourdomain.com
- poolname-webint-yourdomain.com (EE Web services)
- hostname.yourdomain.com (SE Web services)
- owa.yourdomain.com (Outlook Web Access / Web services)
- autodiscover.yourdomain.com (Exchange Autodiscover)
- meet.yourdomain.com
- dialin.yourdomain.com
Solution with federation
Adding the above domains is not enough for environments with federation configured. When I sniffed the network traffic on the client, I found out the Lync client connects to this URL:
CONNECT images.edge.messenger.live.com:443 HTTP/1.1
Host: images.edge.messenger.live.com:443
This URL is being used for federation with Messenger/Skype accounts. Of course, the question remains why this URL is not reachable by using the proxy. But the problem can be resolved by adding this URL to your proxy exceptions: images.edge.messenger.live.com