403 Forbidden on Personal Connection Outbound API

Trying to trigger an outbound call via Personal Connection. Using the /api/v2/voice/outbound/calls endpoint. My service account has voice:outbound:write. The request returns 403 immediately. Here is the JSON payload:

{
 "contactId": "1234",
 "callType": "voice",
 "destination": {"number": "+15550199"}
}

Checked the logs. No specific error message in the response body. Is there a specific permission I’m missing for PC outbound?