4452d530_able___FreeSWITCH___Confluence__Description
[ITU-T Q.850 Code] 57 [SIP Equiv.] 403 [Enumeration] BEARERCAPABILITY_NOTAUTH [Cause] bearer capability not authorized [Q.850] [Description] 
This cause indicates that the user has requested a bearer capability that is implemented by the equipment which generated this cause but the user is not authorized to use.
Hangup Cause Code Table - FreeSWITCH - Confluence
Description