Freepbx 15 attendant issue with sbc

since i migrate the freepbx from router to a sbc . i have a issue .
when my phone received a external call and want to transfer to another phone ( assisted transfer) .
The call stuck on hold . The support of the sbc company said it’s a issue of freepbx .

Your image is too low resolution to read easily. The significance of the addresses is not explained. You haven’t provided the full content of the rejected REFER, and haven’t provided the full content of the INVITE for the session that is the target of the REFER, and if it is a REFER/Replaces, the session being replaced.

Generally, I would expect the full “pjsip set logger on” (or equivalent legacy driver command) output, for all the sessions involved. That should be enough to say why Asterisk is rejecting it, but we’d need the same information for the public network side of the SBC, to understand how the SBC put it in that position.

My guess is that is a remote worker extension, is the public side of the SBC. The trace doesn’t show the linkage between the sides of the SBC, although given that it is accepting the REFER, it would seem that it is acting as a back to back user agent so there are different sessions on each side. is the LAN side of the SBC, and is the machine running Asteirsk.