4f55f5cb_ISDN_Cause_Codes__Cause_Usage
[Cause#] 50 [Fixit!] N/A [Cause Summary] Requested facility not subscribed. [Cause Usage] 
Indicates that the requested supplementary service could not be provided by the network because the user has not completed the necessary administrative arrangements with its supporting networks.
ISDN Cause Codes
Cause Usage