I'm having trouble signing in to MS Lync 2010 client. I have two laptops and need to have the same user credentials log into both, but never simultaneously. One of the laptops logs in flawlessly; the other attempts to log in and just says "Contacting server and signing in" forever. Both laptops are signing in from the same network switch in our building, same network; and both laptops are the same make / model running Windows 7 Pro. I can't understand what the problem is! I have tried copying two certicates over from the working laptop (one in Credentials Manager and the other in certmgr) but this makes no difference. I have also uninstalled the Lync client, removed the "Communicator" folder, and removed two registry entires related to Lync; then reinstalled, and no different. The Microsoft Lync remote connection analyzer test is a success. Any help?

Contacting server and signing in

Are both laptops using the same DNS? Usually, Link servers are identified by the DNS Helper records for SIP. Lync Servers are 'found' on the network with these special DNS records. Usually, sip.mycompany.com will resolve to a lync server to service your client.

Do you have a firewall running on the 2nd machine by any chance that could be blocking ports?

Thanks for the reply. Both laptops are using 'automatic DNS' settings. I have two CNAME records added to my AD server. Note, however, that the actual Lync server is hosted in Germany by our parent company. Support from them is not the easiest. We use a SonicWall firewall, and since the one laptop gets through, my assumption is that the other should as well. One does use a static IP (I have tried switching to automatic but no luck that way either) but the the necessary ports on the firewall are open to all on our LAN for the Lync services.

Check your firewall logs for blocked packets. that should be easy to do if you have the source and destination IP information.

Why would the firewall block packets from one but not the other? Everything is identical.

Well, I've managed a firewall team for several years, some time ago and my experience has been that there is always a possibility that the firewall rule that's in place for this service is only including certain source IPs. Your rule may not include the other computers IP. It's a quick check and worth the effort to rule out a firewall rule issue.

Note that I'm talking about your SonicWall appliance.

Jorge,

Thanks for the reply. I reviewed the sonicwall again, any IP within our LAN can reach out to the specified Lync server WAN(s) for the specified Lync services and likewise, the Lync server WAN(s) can communicate with any LAN IP on our domain for the specified services.

Ok so the spotlight is back on that second machine. Have you tried on a third system to see if this problem follows?

On that problem computer, anything in the event logs indicating a system or communication problem?

I installed the Lync client on my personal workstation...no camera or mic, but I was able to sucessfully login! Same credentials, same domain.

However, I was not able to login on my Apple notebook using the Lync for Mac client. Oddly, on my windows 7 workstation which did login, there are no stored certificates in certmgr or Credentials Manager.

I have two CNAME records added to my AD server.

The Textbook lync setup requires the SIP helper records in DNS.

Look here... this article has the example and the links on how to set it up properly.
https://help.nextuc.com/entries/21807198-How-to-verify-your-DNS-Settings

Can the trouble machine ping and resolve the items as indicated?
Can you manually enter the connection information into the trouble machine's client and have it connect?
Can the trouble machine telnet to the lync server on port 5061 without issue?
Does the trouble machine work from any other location ?

I have solved it, but I'm not sure which change I made solved it:

-Added a public DNS server as our primary and moved our internal DC the alternate (previously only had our internal DC server)

-Enabled IPV6 (previously disabled)

Since it did log in and download the certificate, I tried removing the first, and then second, changes I made...but now it works either way. I believe once Lync 'gets' the certificate it authenticates a different way.

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