Bueno antes que nada gracias adelantadas por la ayuda

les platico que tengo un pbx con elastix 2.2 y hacia y recibía llamadas perfectamente hasta que misteriosamente hoy dejo de recibir llamadas, en el archivo hosts tengo la ip publica de mi pbx y la de mi proveedor de la troncal sip.
en el sip_general_custom.conf también tengo especificado la ip publica de mi pbx,
y puedo hacer llamadas con completa normalidad pero para recibir llamadas ni siquiera las veo el el cli de asterisk

si hago un debug se ve esto


sip set  debug peer 523310XXXXXX
SIP Debugging Enabled for IP: 200.76.112.13
[Sep 14 22:35:06] NOTICE[4961]: chan_sip.c:13968 check_auth: Correct auth, but based on stale nonce received from '"HeliosIP" <sip:200@192.168.2.5>;tag=30888'
REGISTER 11 headers, 0 lines
Reliably Transmitting (NAT) to 200.76.112.13:5060:
REGISTER sip:i2next.com.mx SIP/2.0
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK19bfa96e;rport
Max-Forwards: 70
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as0fbde8c1
To: <sip:878XXXXXXX@i2next.com.mx>
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1170 REGISTER
User-Agent: FPBX-2.8.1(1.8.7.0)
Authorization: Digest username="878XXXXXXX", realm="i2next.com.mx", algorithm=MD5, uri="sip:i2next.com.mx", nonce="5053f845052c5d524a9e1a2a22639fcf58ea06b1", response="a0d79991a095e06329972609e13b3fca"
Expires: 60
Contact: <sip:878XXXXXXX@187.133.XXX.XXX:5060>
Content-Length: 0


---
[Sep 14 22:35:14] NOTICE[4961]: chan_sip.c:12681 sip_reg_timeout:    -- Registration for '878XXXXXXX@i2next.com.mx' timed out, trying again (Attempt #1069)

<--- SIP read from UDP:200.76.112.13:5060 --->
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK19bfa96e;rport=5060
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as0fbde8c1
To: <sip:878XXXXXXX@i2next.com.mx>;tag=dfa406cb245a7bd529187c8528a0918b.df5a
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1170 REGISTER
WWW-Authenticate: Digest realm="i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30"
Server: Inext (1.2.1-notls (i386/linux))
Content-Length: 0

<------------->
--- (9 headers 0 lines) ---
Responding to challenge, registration to domain/host name i2next.com.mx
REGISTER 11 headers, 0 lines
Reliably Transmitting (NAT) to 200.76.112.13:5060:
REGISTER sip:i2next.com.mx SIP/2.0
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK00cdd336;rport
Max-Forwards: 70
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as12084765
To: <sip:878XXXXXXX@i2next.com.mx>
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1171 REGISTER
User-Agent: FPBX-2.8.1(1.8.7.0)
Authorization: Digest username="878XXXXXXX", realm="i2next.com.mx", algorithm=MD5, uri="sip:i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30", response="da8e1aaa6068c46e8a59be3a02ac619f"
Expires: 60
Contact: <sip:878XXXXXXX@187.133.XXX.XXX:5060>
Content-Length: 0


---

<--- SIP read from UDP:200.76.112.13:5060 --->
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK00cdd336;rport=5060
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as12084765
To: <sip:878XXXXXXX@i2next.com.mx>;tag=dfa406cb245a7bd529187c8528a0918b.400f
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1171 REGISTER
WWW-Authenticate: Digest realm="i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30"
Server: Inext (1.2.1-notls (i386/linux))
Content-Length: 0

<------------->
--- (9 headers 0 lines) ---
Responding to challenge, registration to domain/host name i2next.com.mx
REGISTER 11 headers, 0 lines
Reliably Transmitting (NAT) to 200.76.112.13:5060:
REGISTER sip:i2next.com.mx SIP/2.0
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK3f021c09;rport
Max-Forwards: 70
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as64dc981e
To: <sip:878XXXXXXX@i2next.com.mx>
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1172 REGISTER
User-Agent: FPBX-2.8.1(1.8.7.0)
Authorization: Digest username="878XXXXXXX", realm="i2next.com.mx", algorithm=MD5, uri="sip:i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30", response="da8e1aaa6068c46e8a59be3a02ac619f"
Expires: 60
Contact: <sip:878XXXXXXX@187.133.XXX.XXX:5060>
Content-Length: 0


---

<--- SIP read from UDP:200.76.112.13:5060 --->
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK3f021c09;rport=5060
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as64dc981e
To: <sip:878XXXXXXX@i2next.com.mx>;tag=dfa406cb245a7bd529187c8528a0918b.0df2
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1172 REGISTER
WWW-Authenticate: Digest realm="i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30"
Server: Inext (1.2.1-notls (i386/linux))
Content-Length: 0

<------------->
--- (9 headers 0 lines) ---
Responding to challenge, registration to domain/host name i2next.com.mx
REGISTER 11 headers, 0 lines
Reliably Transmitting (NAT) to 200.76.112.13:5060:
REGISTER sip:i2next.com.mx SIP/2.0
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK66464cba;rport
Max-Forwards: 70
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as24d196c6
To: <sip:878XXXXXXX@i2next.com.mx>
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1173 REGISTER
User-Agent: FPBX-2.8.1(1.8.7.0)
Authorization: Digest username="878XXXXXXX", realm="i2next.com.mx", algorithm=MD5, uri="sip:i2next.com.mx", nonce="5053f859ad910bcb50eedc53ccd7b96ae1949c30", response="da8e1aaa6068c46e8a59be3a02ac619f"
Expires: 60
Contact: <sip:878XXXXXXX@187.133.XXX.XXX:5060>
Content-Length: 0


---

<--- SIP read from UDP:200.76.112.13:5060 --->
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 187.133.XXX.XXX:5060;branch=z9hG4bK66464cba;rport=5060
From: <sip:878XXXXXXX@i2next.com.mx>;tag=as24d196c6
To: <sip:878XXXXXXX@i2next.com.mx>;tag=dfa406cb245a7bd529187c8528a0918b.f1b5
Call-ID: 38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1
CSeq: 1173 REGISTER
WWW-Authenticate: Digest realm="i2next.com.mx", nonce="5053f85a6d6fae5807819323f44334a2b19386d6"
Server: Inext (1.2.1-notls (i386/linux))
Content-Length: 0

<------------->
--- (9 headers 0 lines) ---
[Sep 14 22:35:15] NOTICE[4961]: chan_sip.c:20027 handle_response_register: Failed to authenticate on REGISTER to '878XXXXXXX@i2next.com.mx' (Tries 3)
Really destroying SIP dialog '38be655a6bb0a4c63228fbc96d53dce4@127.0.0.1' Method: REGISTER
Really destroying SIP dialog '0d1600f847417eea1d59c16c5e816bb4@127.0.0.1' Method: REGISTER
Really destroying SIP dialog '135398eb6dec5ade79ceafd56392c913@127.0.0.1' Method: REGISTER
localhost*CLI>

sip show peers y sip show registry


5233xxxxxxxx/878xxxxxxx    200.76.112.13                                N      5060     OK (17 ms)
5255xxxxxxxx/878xxxxxxx    200.76.112.13                                N      5060     OK (16 ms)
5281xxxxxxxx/878xxxxxxx    200.76.112.13                                N      5060     OK (17 ms)

i2next.com.mx:5060                      N      878xxxxxxx          45 Registered           Fri, 14 Sep 2012 22:41:43
i2next.com.mx:5060                      N      878xxxxxxx          45 Registered           Fri, 14 Sep 2012 22:41:43
i2next.com.mx:5060                      N      878xxxxxxx          45 Registered           Fri, 14 Sep 2012 22:41:43