I have an SPA9000 and 3 SPA924's (current firmware) connected to an ITSP (iiNet in Australia) working fine.
My issue is when I attempt to transfer a external call from one SPA924 to another it drops the call, be it a blind transfer or when I allow the other SPA924 to pick up, they both result in the external call being dropped.
I have tried setting on the SPA9000 SIP Line 1. CFWD Bridge & XFER Bridge to ALL with no joy.
Force Media Proxy is also enabled.
I can transfer calls internally without problem, only when an external call is being transfered does it fail.
Any help welcomed!