Problème d'appel sur Cisco 303

[StateOfMind]

Bonjour,

J'ai tout fraichement installé mon serveur asterisk sur ma VM (debian 9) en local avec différent module.

J'ai à ma disposition un Cisco 303 (3 lignes)
un softphone Ekiga
un softphone Xlite

Après avoir configurer sip.conf

[general]

context = default
bindport = 5060
bindaddr = 0.0.0.0
language = fr
srvlookup = yes
disallow = all
allow = alaw
allow = ulaw
allow = gsm


[1010]

language = fr
type = friend
defaultuser = 1010
callerid = "jean" <1010>
host = 192.168.1.20
qualify = yes
nat = no

[1020]

language = fr
type = friend
defaultuser = 1020
callerid = "dupont" <1020>
host = dynamic
qualify = yes
nat = no


[1030]

language = fr
type = friend
defaultuser = 1030
callerid = "pierre" <1030>
host = dynamic
qualify = yes
nat = no
et extensions.conf

[general]

autofallthrough = yes
static = yes
writeprotect = no



[globals]

jean = sip/1010
dupont = sip/1020
pierre = sip/1030


[default]
exten => 1010, 1, Answer()
exten => 1010, 2, Dial(Sip/1010, 10)
exten => 1010, 3, Hangup()

exten => 1020, 1, Answer()
exten => 1020, 2, Dial(Sip/1020, 10)
exten => 1020, 3, Hangup()

exten => 1030, 1, Answer()
exten => 1030, 2, Dial(Sip/1030, 10)
exten => 1030, 3, Hangup()



1010 = cisco 303
1020 = Ekiga
1030 = Xlite

je ping tout mes clients

et ceci apparait quand je fais un appel depuis 1020 vers 1010

== Using SIP RTP CoS mark 5
> 0x7fbaa00107a0 -- Strict RTP learning after remote address set to: 192.168.1.33:5062
-- Executing [1010@default:1] Answer("SIP/1020-000000be", "") in new stack
> 0x7fbaa00107a0 -- Strict RTP learning after remote address set to: 192.168.1.33:5062
> 0x7fbaa00107a0 -- Strict RTP switching to RTP target address 192.168.1.33:5062 as source
-- Executing [1010@default:2] Dial("SIP/1020-000000be", "Sip/1010, 10") in new stack
== Using SIP RTP CoS mark 5
-- Called Sip/1010
-- SIP/1020-000000be requested media update control 20, passing it to SIP/1010-000000bf
== Everyone is busy/congested at this time (1:0/0/1)
-- Auto fallthrough, channel 'SIP/1020-000000be' status is 'CHANUNAVAIL'
> 0x7fbaa00107a0 -- Strict RTP learning complete - Locking on source address 192.168.1.33:5062

alors que la ligne n'est pas occupé

Quelqu'un aurait une idée du problème ?