Have a user logged in on his Lync 2013 mobile client . The use is member of a Respnsegroup. When the someone call this responsegroup Lync mobile client is unable to establish a connection.

 I have found several others that also have this problem, and it seem that this is by design – not supported. According to Technet : http://technet.microsoft.com/en-us/library/gg398674.aspx

Clients that are supported :

• Lync 2013
• Lync 2010
• Lync 2010 Attendant
• Office Communications Server 2007 R2 Attendant
• Lync Phone Edition