POST /api/v2/conversations/calls 403 when trying to initiate outbound call via Kotlin SDK

Is the correct approach to use the conversationsApi.createCallConversation method for initiating an outbound call on behalf of an agent, or should I be hitting the REST endpoint directly? I’m building a Kotlin utility in Android to trigger outbound calls from our internal app, but I keep getting a 403 Forbidden response when trying to post to /api/v2/conversations/calls. The code looks like this:

val callRequest = CallConversationRequest(
 to = listOf("+15551234567"),
 from = "+15559876543",
 routing = CallRoutingObject(
 type = "queue",
 queueId = "abc-123-xyz"
 )
)
val response = conversationsApi.createCallConversation(callRequest)

I’ve verified the OAuth token has the conversation:call:create scope. The endpoint works fine in Postman with the same token. The error payload says Access to resource is forbidden. I’m using the genesys-cloud-kotlin-client SDK version 2.4.0. The agent is online and available in the queue. I’ve tried swapping the token for a long-lived service account token with full admin rights, but it still fails. The stack trace doesn’t show much detail beyond the 403. Is there a specific permission missing on the service account or a weird quirk with the Kotlin SDK client builder?