Symptoms
Assume that you complete the registration with the serversuccessfully . If there are issues in loading the cache pool, and the cache pool cannot be loaded completely, you get stuck in signing in Microsoft Skype for Business 2015 (Lync 2013).
Resolution
To fix this issue, install the December 6, 2016, update (KB3127976) for Skype for Business 2015 (Lync 2013).Note Lync 2013 was upgraded to Skype for Business in April 2015.
