"Cannot connect to the server" error message when Lync Online users try to sign in to the Lync 2010 mobile client on a mobile device

A Lync Online user tries to sign in to the Microsoft Lync 2010 mobile client from a Windows Phone 7, Apple iPhone or iPad, Google Android, or Nokia Symbian device by using the Auto-Detect Server option to determine the Lync Online server. However, the user receives the following error message:

This issue occurs if the Lync Mobile Autodiscover process fails and the user's Lync Online server cannot be determined. This issue may occur if one of the following conditions is true:

• The Lyncdiscover CNAME record is not set up.
• The Lyncdiscover CNAME record is set up incorrectly.
• The Wi-Fi connection is blocking DNS queries.

For the Lync Mobile Auto-Detect Server option, specific CNAME records must be present in DNS for the Lync 2010 mobile client to determine the home server of the Lync Online user. The Lync 2010 mobile client tries to discover the user's home server by querying the following CNAME records in DNS:

• LyncdiscoverInternal.<domain>
• Lyncdiscover.<domain>

Additionally, the CNAME records in DNS must meet the following criteria. Otherwise, the Lync Mobile sign-in process will fail if the Auto-Detect Server option is used.

• DNS Record Type: CNAME
• Name: Lyncdiscover
• Value/Destination: webdir.online.lync.com

To troubleshoot this issue, follow these steps.

Step 1: Verify the Lyncdiscover CNAME record

To verify that the Lyncdiscover CNAME record is present in DNS, use the nslookup command to verify the Lyncdiscover CNAME record on the computer. To do this, follow these steps:

1. Click Start, clickRun, type cmd in theOpenbox,and then press Enter.
2. Type the following command, and then press Enter:
   
   
   nslookup –type=CNAME –server=4.2.2.2 lyncdiscover.contoso.com
   Note Replace contoso.com with the domain suffix of the user who is experiencing the sign-in issues.
   
   The output should resemble the following:
   
   

   C:\Windows\System32>Nslookup -type=CNAME –server=4.2.2.2 lyncdiscover.contoso.com Server: Unknown Address: 192.168.1.254
   Non-authoritative answer: lyncdiscover.contoso.com canonical name = webdir.online.lync.com

   Note To verify that both public and private DNS servers can resolve the CNAME record, perform this test with and without the "-server=4.2.2.2" option.

Step 2: Try a Wi-Fi connection

After you verify that the Lyncdiscover CNAME record exists in DNS, check whether a Wi-Fi connection is available. If a Wi-Fi connection is available, try to connect to Lync Online. This test determines whether the DNS lookup failure is occurring on the mobile carrier, the Wi-Fi connection, or both.

Step 3: Query DNS from the mobile carrier

The next step to check whether the mobile device can resolve the Lyncdiscover CNAME record in DNS is to query DNS from the phone itself. This is difficult to do because most mobile devices do not include integrated network diagnostic tools. So, users have to download an application that performs these kinds of functions. Demonstrating the use of these applications is outside the scope of this article and outside the scope of Office 365 Technical Support.

Note For Applie iPhone or iPad, you may choose to use the DNS Lookup+ application, which is available through the Apple App Store. It can perform DNS lookup by using the mobile carrier's DNS servers instead of routing the request through a proxy server. At this time, we do not have any similar suggestions for Windows Phone 7, Google Android, or Nokia Symbian. If such an application becomes available, we will update this article with that information.

For more information about Lync Mobile client devices, click the following article numbers to view the articles in the Microsoft Knowledge Base: The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.