POST /api/v2/conversations/calls 403 Forbidden on agent behalf

Getting a 403 Forbidden when trying to initiate an outbound call via the Conversations API.

POST /api/v2/conversations/calls
{
 "from": { "phoneNumber": "+18005550199" },
 "to": [{ "phoneNumber": "+13105550100" }],
 "providerId": "genesys",
 "wrapUpCode": { "id": "default" }
}

The token has conversation:write and call:write scopes. The agent is currently in Available state. I’ve verified the number is configured for outbound. What am I missing?