We’re a small clinical research site running Zoom Phone Pro, 4 users on the US/CA Unlimited Calling Plan, with a Server-to-Server OAuth app that has all the phone:*:admin scopes. We’re trying to assign a custom voicemail greeting to a user extension via PATCH /phone/extension/{extensionId}/call_handling/settings/call_handling, setting routing.voicemail_greeting. The call returns HTTP 204, but the greeting never actually persists — a follow-up GET still shows the default. The odd part is that sibling fields in the very same request (max_wait_time, ring_mode) do save, so it looks less like a bad payload and more like a per-field licensing/tier gate. We see the same silent no-op on the auto-receptionist …/ivr PATCH. Since we’re still small, I’m guessing this might just be a licensing thing, so could this command be enabled for our license, or is the web UI the only supported path for greeting/IVR writes? Thanks in advance.