Stop recording? or stop playing?

HI…
I’m recording all calls from pstn usin MixMonitor()
but i don’t know why, but when i playback the file, the file is just played only like for 20 seconds and then hangup, i don’t know why but i’m recorind all calls from internal too and these records are recorded and played really fine using the same app “MixMonitor()”

PLEASE HELP ME!