Call bug..asterisk won't call anymore after a while

after a while asterisk will not make the call.

in the console I have like this:

executing dial(SIP…, OH…) in new stack

and then asterisk stops…

it should go further and choose the codec

like :
H323 executing call to… with codec(s)…

do you know what is the problem ? is it a codec issue ? H323 issue ?
I run asterisk on Debian Linux, with their package, 1.0x version