Congestion cause 34 on E1 Sangoma

Hello everybody,

I’m having an annoyng problem on my system:
On high load traffic (only out bound) I get a lot of congestion cause 34
[Mar 20 16:41:42] WARNING[4372] app_dial.c: Unable to create channel of type ‘dahdi’ (cause 34 - Circuit/channel congestion)
It is a random behavior and affects adjoining calls.
The TELCO does not receive this call
I hope someone could help me.
Thanks.

I post some information
openSUSE 11.3 (x86_64)
VERSION = 11.3
:~ # rpm -qav | grep dahdi
dahdi-tools-2.4.1-52.1.x86_64
dahdi-kmp-default-2.4.1.2_k2.6.34.10_0.2-24.1.x86_64
dahdi-tools-devel-2.4.1-52.1.x86_64
asterisk-vici-dahdi-1.4.39.2-11.2.x86_64
dahdi-2.4.1.2-24.1.x86_64
:~ # rpm -qav | grep libpri
libpri-1_4-0-1.4.11.5-15.1.x86_64
libpri-1_4-1.4.12-18.1.x86_64
ASTERISK version: 1.4.39.2
SANGOMA CARD A102 PRI E1

chan_dahdi.conf:

[trunkgroups]

[channels]
context=default
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
canpark=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=yes
relaxdtmf=yes
rxgain=0.0
txgain=0.0
group=1
callgroup=1
pickupgroup=1
immediate=no
callprogress=yes
pridialplan=unknown
prilocaldialplan=unknown
nationalprefix=0
internationalprefix=00
;Sangoma A102 port 1 [slot:4 bus:2 span:1]
switchtype=national
context=default
group=1
echocancel=yes
signalling=pri_cpe
channel =>1-15,17-31

;Sangoma A102 port 2 [slot:4 bus:2 span:2]
switchtype=national
context=default
group=1
echocancel=yes
signalling=pri_cpe
channel =>32-46,48-62