Sip Maximum retries exceeded on transmission

Apr 19 10:04:50 WARNING[1295]: chan_sip.c:1228 retrans_pkt: Maximum retries exceeded on transmission bc1f352ae80cc956Mzc1ZWZkOWEzNjhiMDk4MDM3YjVmZjg0MTYxZmM3ZjE. for seqno 2 (Critical Response)

Apr 19 10:05:35 WARNING[1295]: chan_sip.c:1245 retrans_pkt: Hanging up call 94446b1ecc252e5eMzc1ZWZkOWEzNjhiMDk4MDM3YjVmZjg0MTYxZmM3ZjE. - no reply to our critical packet.

0 && && 11&& 1
Apr 19 10:05:35 WARNING[1788]: file.c:587 ast_readaudio_callback: Failed to write frame

I have this problem too. On a LOCAL network; this problem does not happen. Only when I try to attach SIP devices over a VPN.

I tried many things, too many to remember. For certain, NAT=NO does not fix it. I am now seeking professional help from my network consultant to track and trace the network activity testing the difference in conditions locallay VS vpn.

For anyone else’s information; this was resolved when I added:

localnet x.x.x.x/s.s.s.s

to the [GENERAL] context of sip.conf. (replace x.x.x.x with ip address and s.s.s.s with subnet mask of remote local network)