Assume that you assign a Session Initiation Protocol (SIP) Uniform Resource Identifier (URI) address that only contains numbers to a user in a Microsoft Lync Server 2010 environment. For example, the address that you assign the user is email@example.com. In this situation, the picture of the user is displayed as a telephone in Microsoft Lync 2010 for iPhone. Additionally, other users cannot send instant messages to this user.
This issue occurs because Lync 2010 for iPhone incorrectly treats the SIP URI address that only contains numbers as a telephone contact.
To resolve this issue, install the following cumulative update:
2673223 Description of the cumulative update package for Lync 2010 for iPhone: March 2012