MOH starting and stoping issue


I am facing strange issue in asterisk.

Dial plan
exten => _X.,1,Answer
exten => _X.,2,MusicOnHold(test)
exten => _X.,3,Hangup

MOH class

when i call this test dial plan it play the MOH file. Initially its playing MOH without any interruption. But after few minutes MOH is suddenlty stop for the few seconds and then start again, this thing happen continuously.

Please help me to fix this issue…

I am not getting any idea about this issue.

Thanks in Advance.