This issue occurs when you transfer a call by clicking the Parking Lot option in a Microsoft Lync Server 2013 environment that has Call Park service enabled.
When this issue occurs, the call cannot to be parked.
Cause
This issue occurs because Call Park service does not commit the orbit number.
Resolution
To resolve this issue, install the July 2015 cumulative update 5.0.8308.920 for Lync Server 2013.