Incoming calls dropped!

Asterisk Asterisk Support
1

I have a problem with dropped incoming calls.
I does not always happen, but when it happens it is normally some 20s into the call.
Asterisk endup with:

Mar 17 13:12:53 WARNING[2628] chan_sip.c: Maximum retries exceeded on transmission 373381d151a2f29113fce2a11193496b@x.x.x.x for seqno 102 (Critical Response)
Mar 17 13:12:53 WARNING[2628] chan_sip.c: Hanging up call 373381d151a2f29113fce2a11193496b@x.x.x.x - no reply to our critical packet.

Wireshark seq:
Request: INVITE sip:1@x.x.x.x:5060, with session description
Status: 100 Trying
Status: 200 OK, with session description
Request: INVITE sip:1@x.x.x.x:5060, with session description
Request: INVITE sip:1@x.x.x.x:5060, with session description
Request: ACK sip:1@x.x.x.x:5060
Status: 200 OK, with session description
Status: 200 OK, with session description
Request: ACK sip:1@x.x.x.x:5060
Request: ACK sip:1@x.x.x.x:5060
Status: 200 OK, with session description
Request: ACK sip:1@x.x.x.x:5060
Status: 200 OK, with session description
Request: ACK sip:1@x.x.x.x:5060
Status: 200 OK, with session description
Request: ACK sip:1@x.x.x.x:5060
Status: 200 OK, with session description
Request: ACK sip:1@x.x.x.x:5060
goes on until Asterisk drops the call

I am no SIP expert, but why do I get 3 INVITE for the same call (a logged OK call did only contain 1 INVITE)
So, this is maybe not an Asterisk problem?
It seems my Asterisk sends OK and other end ACK but somehow my Asterisk does not see this ACK.
Is it confused of what belongs to what here?

2

On the contrary, it reads to me that Asterisk receives OK and sends ACK. I’m no SIP expert but it doesn’t look normal to having the same dialogue multiple times for one call. You’ll have to give more detail for others to help, e.g., what Asterisk version, relavant segments of sip.conf, dial plan, any pattern/triggering event when this happens, etc. (Might even be simple latency issue.)

BTW, you could turn on sip debug and save the trip with Wireshark.