Problem in recording

hi all,

This my manager API commands used for recording,

ACTION: Monitor
Channel: "specified channel"
File: channelsavefile
Mix: 1

“specified channel”== this channles id is got from redirect command in manager API,

my problem is,

The recording file is created in the path /var/spool/asterisk/monitor…but the recording content is not stored in the file name… the file was empty …

help me out .