music on hold stopped before ringing

this is the ast message when i call a local sip exten:

[Jun 3 15:12:10] WARNING[29008]: l4isup.c:5059 l4isup_event: Received IAM (CIC 9), link '11'.
-- Recv IAM CIC=9 ANI=0153******9 DNI=2227101 RNI= redirect=no/0 complete=0
-- Executing [2227101@mohtest:1] Set("SS7/1/9", "CALLERID(rdnis)=2227100") in new stack
-- Executing [2227101@mohtest:2] Dial("SS7/1/9", "SIP/90001,60,m(defaultmoh)") in new stack

== Using SIP RTP CoS mark 5
-- Called SIP/90001
-- Started music on hold, class 'defaultmoh', on SS7/1/9
-- Stopped music on hold on SS7/1/9
-- SIP/90001-00000003 is ringing
-- SIP/90001-00000003 answered SS7/1/9
[Jun 3 15:12:24] WARNING[29008]: l4isup.c:5059 l4isup_event: Received REL (CIC 9), link '11'.
== Spawn extension (mohtest, 22227101, 2) exited non-zero on 'SS7/1/9'
-- SS7 hangup 'SS7/1/9' CIC=9 Cause=16 (state=7)

Hi,
Please chcek your media 'defaultmoh', you can replace it by 'demo-instruct' and try again!

but there is only one classes 'defaultmoh':

localhost*CLI> moh show classes
Class: defaultmoh
Mode: files
Directory: /var/lib/asterisk/moh/defaultmoh
localhost*CLI>

Please move away all media in /var/lib/asterisk/moh/defaultmoh, and copy /var/lib/asterisk/sound/en/demo-instruct.gsm to /var/lib/asterisk/moh/defaultmoh. Then reload asterisk and try agian.

oops, the same result...

Please enable the debug message and send the log file to me. My Email: This email address is being protected from spambots. You need JavaScript enabled to view it.