Plantronics + Polycom.
Now together as
We have a HDX 8000 HD and we are having intermittant trouble calling one of our international endpoints. We use a Cisco VCS-E as our gateway and a VCS-Control for registration.
We have recently recieved this error on the endpoint when calling "the user is not authorized to use the requested bearer capability".
I searched the web and found that this message points me to an ISDN #57 error code. Our HDX has never has ISDN configured on it and we do not use ISDN anywhere else.
We can call the international endpoint with other Polycom system on campus without the issue.
How did you go with that?
I was working on a Real Presence / Group Series 500 this week and encountered the same error when I was trying to integrate it with Skype for Business.
The issue occurred when I was trying to make an outgoing call to a PSTN destination.
A reboot fixed it.
I hope this might help the next person who who finds their way here.