I recently purchased a HT-503 to use it as a FXO Gateway with FreePBX. After spending some time to configure it with lots of web tutorials, I'm able to receive calls and forward them to my IPBX and everything works. When I try to make an outbound call I receive an error of chan_sip.c:4071 retrans_pkt: Retransmission timeout reached on transmission...
So I try to debug sip connection and it seems like the HT-503 doesn't make the ACK response.
Any Ideas to how set it or configure it correctly?
Thanks in advance.