4452d530_able___FreeSWITCH___Confluence__Description
[ITU-T Q.850 Code] 27 [SIP Equiv.] 502 [Enumeration] DESTINATION_OUT_OF_ORDER [Cause] destination out of order [Q.850] [Description] 
This cause indicates that the destination indicated by the user cannot be reached because the interface to the destination is not functioning correctly. The term "not functioning correctly" indicates that a signal message was unable to be delivered to the remote party; e.g. a physical layer or data link layer failure at the remote party, or user equipment off-line.
Hangup Cause Code Table - FreeSWITCH - Confluence
Description