I am making a new post as I realize I did not fully understand the issue previously (sorry).
Due to STIR/SHAKN and Twilio rules, external transfers like in a call forward scenario, must be initiated in the original inbound SIP dialog. When looking up the proper application, it seems that using "Deflect" SHOULD do that. Now, when I change "call_forward_all" dialplan to deflect instead of transfer, nothing happens. I have attached what my log shows for this action. There is nothing sent in the SIP flow and the call just terminates.
Twilio has a good diagram if someone needs a visual of the proper flow. https://www.twilio.com/docs/sip-trunking/call-transfer
Due to STIR/SHAKN and Twilio rules, external transfers like in a call forward scenario, must be initiated in the original inbound SIP dialog. When looking up the proper application, it seems that using "Deflect" SHOULD do that. Now, when I change "call_forward_all" dialplan to deflect instead of transfer, nothing happens. I have attached what my log shows for this action. There is nothing sent in the SIP flow and the call just terminates.
Twilio has a good diagram if someone needs a visual of the proper flow. https://www.twilio.com/docs/sip-trunking/call-transfer