Problem with IAX o codec

Hi i have the gateway and 2 client.
The gateway is connect with the trunk IAX to client.
Many call is hungup strange.
This is the messagges

Call accepted by 3333333 (format gsm)
Executing Dial(‘IAX2/XXX:11111@3333333/XXXXXXXXXXXX’)
Called IAX2/XXX:11111@3333333/XXXXXXXXXXXX
VERBOSE[982] chan_iax2.c: – Call accepted by 3333333 (format gsm)
VERBOSE[982] chan_iax2.c: – Format for call is gsm
VERBOSE[4888] app_dial.c: – IAX2/host05-1042 is ringing
VERBOSE[4888] app_dial.c: – IAX2/host05-1042 stopped sounds
VERBOSE[4888] app_dial.c: – IAX2/host05-1042 answered SIP/600-00000005
VERBOSE[968] dnsmgr.c: > Refreshing DNS lookups.

What i see for resolve the problem?

The log shows a successful call!

Yes but the duration call is 00:001 o max 00:003
But no all call but many

If you want to show timings, use the log files, not a screen scrape, and make sure you include the end of the call.

If this were SIP, you would want the log from the remote side,but I don’t know enough about IAX to know if it has the same possible behaviour as the SIP late offer case with incompatible codecs. Again for SIP you would want sip debugging along with core debug level 5, to see what codecs were being offered. I presume the equivalent debugging tools are available for IAX.

I have the debug IAX on gateway
There is someone thats help me?