4452d530_able___FreeSWITCH___Confluence__Description
[ITU-T Q.850 Code] 69 [SIP Equiv.] 501 [Enumeration] FACILITY_NOT_IMPLEMENTED [Cause] requested facility not implemented [Q.850] [Description] 
This cause indicates that the equipment sending this cause does not support the requested supplementary services.
Hangup Cause Code Table - FreeSWITCH - Confluence
Description