GSM Problem - Unable to create channel of type 'Zap' (cause

Hi all.
I've a linux box with 4 GSM SIMs installed.
All seems work fine on a cellular phone.
Astterisk (Zap) see this four SIM like channels 1,3,5,7
It seems that only channel 5 works (also if I change the orde in which the SIMs are inserted).
First call work properly, but if I try to make another outbound call, it appear this message

-- Executing Dial("SIP/192.168.57.7-081608b8", "Zap/7/331xxxxxxxx") in new stack
Jan 31 11:30:39 NOTICE[19578]: app_dial.c:1079 dial_exec_full: Unable to create channel of type 'Zap' (cause 0 - Unknown)
== Everyone is busy/congested at this time (1:0/0/1)


This is for channel 7 (Zap/7), but it happens the same thing also with channels 1 and 3.

Any idea?

Thanks a lot.

Daniele

Hi
Welcome to voipuser.

What is the card that the sims are connected to and to be hinest with dialplan or zapata.conf to look at theres not much that can be said that isnt guesswork. Post the confs and mabe we can see whats going on

Ian