Calls drops after 20 seconds

When we make outgoing calls, the call cuts off after 20 seconds…

The following message is logged in asterisk logs:

chan_sip.c: Maximum retries exceeded on transmission 3dfa7412c350-fr67xe4551hx@192-168-0-40 for seqno 2 (Critical Response) – See doc/sip-retransmit.txt.

WARNING[1154] chan_sip.c: Hanging up call 3dfa7412c350-fr67xe4551hx@192-168-0-40 - no reply to our critical packet (see doc/sip-retransmit.txt).

The hardware phones connecting to asterisk is behind a nat router. I guess this is causing the problem but i have no clue how to fix it. I defined canreinvite=no but it didnt help…

Any help would be appreciated,



have a look in your sip.conf for the nat options.