Article ID: 2833618 - View products that this article applies to.
When a user tries to sign in to Microsoft Lync 2013 in a Lync Server 2013 environment for the first time, the user receives the following message in a dialog box:
Lync is attempting to connect to:
<Fully qualified domain name (FQDN) of a server>
Lync cannot verify that the server is trusted for your sign-in address. Connect anyway?
For example, the following Trust Model dialog box appears:
Collapse this imageExpand this image
This issue occurs because the SIP domain name of the user does not match the domain names in the following properties in the certificate of the Lync Web Service:
To work around this issue, use one of the following methods:
Method 1: Manually modify the TrustModelData registry valueImportant This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs.
For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/322756)How to back up and restore the registry in Windows
To manually modify the TrustModelData registry value for the user, follow these steps:
Method 2: Use Group Policy to modify the TrustModelData registry valueUse Group Policy to modify the TrustModelData registry value for the user.
For more information about the Lync 2013 Trusted Domain List (TrustModelData) Group Policy, see Configuring Client Bootstrapping Policies
For more information about the Lync 2013.admx (ADMX) and .adml (ADML) Administrative Templates, see Office 2013 Administrative Template files (ADMX/ADML) and Office Customization Tool
The Lync 2013 desktop client uses the new automatic discovery mechanism to locate the Internal or External Lync Web Service, depending on the network location of the user.
The following process occurs when the Lync 2013 desktop client tries to locate the Lync Web Service: