Does Vapi's BYO SIP Trunk support transfer calls via REFER?
It seems Vapi supports "native" SIP trunk integrations with Plivo, Telnyx and Zadarma.
However, we are trying to integrate to a SIP Trunk from Twilio (it must be the case, we can't use Vapi's Twilio native integration).
The SIP integration for making and receiving calls works well, but we can't get the call transfer to work.
Despite having Call Transfer enabled in the Twilio SIP Trunk we are integrating with, it seems that Vapi is not sending the REFER packet to Twilio as we don't see a child call or the packet itself in the call's PCAP log.
Does anyone know everything about this? Does Vapi send REFER packets in BYO SIP integrations? How should it be enabled?
However, we are trying to integrate to a SIP Trunk from Twilio (it must be the case, we can't use Vapi's Twilio native integration).
The SIP integration for making and receiving calls works well, but we can't get the call transfer to work.
Despite having Call Transfer enabled in the Twilio SIP Trunk we are integrating with, it seems that Vapi is not sending the REFER packet to Twilio as we don't see a child call or the packet itself in the call's PCAP log.
Does anyone know everything about this? Does Vapi send REFER packets in BYO SIP integrations? How should it be enabled?
