Hello Retell team, I experienced a serious issue with the call transfer functionality while testing my voice agent for a client. I configured the call transfer using SIP INVITE and set the destination number to the client’s phone number. However, during real calls, the transfer did not go to the configured number, but instead it was redirected to a completely different client. This caused a major problem because the client noticed the issue during testing and unfortunately I lost the customer due to this incident. I would like to understand: How it is possible that a SIP INVITE transfer redirects to a different number than the one configured. If there are known issues with SIP INVITE transfers in the current Retell setup. Whether there are best practices or safer ways to configure transfers (for example via phone number transfer instead of SIP). If there are logs available to verify exactly where the call was sent. This is a critical feature for my product because I am deploying AI voice agents for clients, and incorrect transfers can seriously damage client trust. Could you please help me investigate what happened? Agent: agent_e51a12781f1ac0ccbc759509b0 Call ID: call_84b29c0d02da4d9b299392828a7 I have encountered this problem on several calls

Hi @Matteo

Let me know when you have any update @Shah - support @ Retell AI

Hi @Matteo We thoroughly investigated call call_84b29c0d02da4d9b299392828a7, including internal logs and SIP traces. The transfer was routed to +39051613xxxx, which was the exact number configured as the predefined transfer destination in your transfer_call tool at the time of the call. The system correctly dialed the number set in your agent's configuration. We see the transfer destination has since been updated, so this should now be resolved going forward. As a best practice, please verify the transfer destination number in your agent's tool settings whenever you create or modify an agent, especially if managing multiple agents with different transfer numbers.

Thanks, you can close

Hi @Matteo