Architect Call Control Block Fails for Teams Direct Routing Endpoints

The Architect flow at node cc_block_04 keeps throwing CALL_CONTROL_FAILED (ERR_503_GATEWAY_TIMEOUT) when routing to Teams direct routing endpoints, even though SBC config in the Teams admin center matches the official documentation (https://learn.microsoft.com/en-us/microsoftteams/direct-routing-sbc) and PowerShell Get-CsOnlineVoiceRoutingPolicy doesn’t flag any gaps. Console returns this payload during the outbound attempt:

{
 "error": "PR_403_SCOPE_MISMATCH",
 "target": "teams_direct_routing",
 "flow_version": "2.4.1"
}

Logs show the handshake stalls. Retry policy isn’t doing jack all.