Mar 19 12:03:20 asterisk[21700]: WARNING[21725]: chan_sip.c:3718 in retrans_pkt: Retransmission timeout reached on transmission M2M5MDg0OTk3ZTRlNzlmZDVjYzIxODVmZTA4MTdkY2Y for seqno 2 (Critical Response) -- See https://wiki.asterisk.org/wiki/display/
в сети все хорошо работает