I can ring out successfully requesting:

https://platform.ringcentral.com/restapi/v1.0/account/~/extension/~/ring-out

But when I want to add the extension id I get a CMN-102 error (Resource for parameter [extensionId] is not found) see request example below:

https://platform.ringcentral.com/restapi/v1.0/account/~/extension/279580017/ring-out  

I'm pretty certain I have the correct id as I'm grabbing the extension Id from the request below successfully:

https://platform.ringcentral.com/restapi/v1.0/account/~/extension 

If anyone has run into this or can point out any potential pitfalls I would very much appreciate some pointers.