Retransmission Timeout after 32 seconds

[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] pbx.c:     -- Executing [s@example-queue:1] Queue("DAHDI/3-1", "example,rtnC,18") in new stack
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] netsock2.c:   == Using SIP RTP CoS mark 5
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] netsock2.c:   == Using SIP RTP CoS mark 5
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] app_queue.c:     -- SIP/123-00002af0 is ringing
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] app_queue.c:     -- SIP/137-00002af1 is ringing
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] app_queue.c:     -- SIP/137-00002af1 is ringing
[2015-05-08 16:07:15] VERBOSE[22380][C-00001d17] app_queue.c:     -- SIP/137-00002af1 is ringing
[2015-05-08 16:07:25] VERBOSE[22380][C-00001d17] app_queue.c:     -- SIP/123-00002af0 answered DAHDI/3-1
[2015-05-08 16:07:25] VERBOSE[22380][C-00001d17] res_rtp_asterisk.c:        > 0x7f29a8011f80 -- Probation passed - setting RTP source address to 10.10.33.35:11790
[2015-05-08 16:07:57] WARNING[21037] chan_sip.c: Retransmission timeout reached on transmission 2c28ab2b0e365949175e6ec44af68f49@10.10.32.251:5060 for seqno 103 (Critical Request) -- See https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions Packet timed out after 32000ms with no response
[2015-05-08 16:07:57] WARNING[21037] chan_sip.c: Hanging up call 2c28ab2b0e365949175e6ec44af68f49@10.10.32.251:5060 - no reply to our critical packet (see https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions).
[2015-05-08 16:07:57] VERBOSE[22380][C-00001d17] pbx.c:   == Spawn extension (example-queue, s, 1) exited non-zero on 'DAHDI/3-1'
[2015-05-08 16:07:57] VERBOSE[22380][C-00001d17] sig_analog.c:     -- Hanging up on 'DAHDI/3-1'
[2015-05-08 16:07:57] VERBOSE[22380][C-00001d17] chan_dahdi.c:     -- Hungup 'DAHDI/3-1'