I distortion, noise calls

Hi I have problems with elastix center, sometimes nothing, in so-called distortion or noise is escuha both outgoing calls and internal, and the central strip me these messages, help me please

Connected to Asterisk 11.17.1 currently running on pbx-istmo-center (pid = 3523)
[2015-06-25 16:26:37] WARNING[8818][C-00000539]: func_presencestate.c:132 presen ce_read: PRESENCE_STATE unknown
[2015-06-25 16:26:41] WARNING[8820][C-0000053a]: func_presencestate.c:132 presen ce_read: PRESENCE_STATE unknown
[2015-06-25 16:29:04] WARNING[8831][C-0000053e]: channel.c:4862 ast_prod: Proddi ng channel ‘SIP/1105-0000064a’ failed
[2015-06-25 16:33:09] NOTICE[3745][C-00000544]: chan_sip.c:10482 process_sdp: No compatible codecs, not accepting this offer!
[2015-06-25 16:36:12] WARNING[8895][C-00000551]: translate.c:343 framein: no samples for alawtolin
[2015-06-25 16:36:16] WARNING[3745][C-00000555]: chan_sip.c:9996 process_sdp: Ignoring audio media offer because port number is zero
[2015-06-25 16:36:16] WARNING[3745][C-00000555]: chan_sip.c:10426 process_sdp: Failing due to no acceptable offer found
[2015-06-25 16:37:06] WARNING[8939][C-0000055e]: func_presencestate.c:132 presence_read: PRESENCE_STATE unknown
[2015-06-25 16:37:14] WARNING[8942][C-00000560]: translate.c:343 framein: no samples for alawtolin
[2015-06-25 16:37:29] NOTICE[3745]: chan_sip.c:29729 sip_poke_noanswer: Peer ‘1131’ is now UNREACHABLE! Last qualify: 0
[2015-06-25 16:37:29] WARNING[8948][C-00000563]: channel.c:4862 ast_prod: Prodding channel ‘SIP/6665-00000669’ failed
[2015-06-25 16:37:54] NOTICE[3745][C-0000056c]: chan_sip.c:10482 process_sdp: No compatible codecs, not accepting this offer!
[2015-06-25 16:39:40] WARNING[8996][C-00000575]: func_presencestate.c:132 presence_read: PRESENCE_STATE unknown
[2015-06-25 16:40:37] WARNING[9025][C-0000057c]: func_presencestate.c:132 presence_read: PRESENCE_STATE unknown
[2015-06-25 16:42:02] NOTICE[3745]: chan_sip.c:29729 sip_poke_noanswer: Peer '103pbx-istmo-center*CLI> WARNING[8818][C-00000539]::