Sorry, the feature is not available in sandbox. If this is critical for your app development project, open a support ticket and request for enable it.

@Phong Vu

I raised a ticket and the only response I'm getting is telling me to upgrade to premium or ultimate and pay $44 per user per month. Is this correct? We're a call recording ISV looking to develop an integration to import recordings into our cloud platform. It seems strange that RC have a sandbox version that's free for devs but of no use for a call recording integration?

No, this is not correct. Give me your sandbox account main company number.