Hi VAPI team! Urgent issue with call transfers using Telnyx SIP trunk. Problem: Outbound call transfer fails — VAPI shows "Transfer Completed Successfully" but immediately drops with "Call ended due to transfer failure" Telnyx confirmed: SIP REFER is accepted on their end and forwarded to VAPI IP 44.238.177.138 but VAPI server returns 503 Service Unavailable — this is a VAPI-side bug. Call ID: 019d49b4-82b3-7ffa-90f2-287c34383369 Org ID: c08e0686-1b2b-49c4-8a89-db03539cc5ea Please help! 🙏