Voicemail does not save into spool directory

Currently I am setting up voicemail.

However, after I done leaving a voicemail and hangup, the .wav voicemail file doesn’t save into the following directory:

Executing [3903@iax2user:10] VoiceMail(“SIP/extension-0b517558”, “extension@context-name”) in new stack
– <SIP/extension-0b517558> Playing ‘vm-intro’ (language ‘en’)
– <SIP/extension-0b517558> Playing ‘beep’ (language ‘en’)
– Recording the message
– x=0, open writing: /var/spool/asterisk/voicemail/context-name/extension/tmp/e3yrSE format: wav49, 0xb256d80
– User ended message by pressing #
– <SIP/extension-0b517558> Playing ‘auth-thankyou’ (language ‘en’)
– <SIP/extension-0b517558> Playing ‘vm-review’ (language ‘en’)
– Saving message as is
– <SIP/extension-0b517558> Playing ‘vm-msgsaved’ (language ‘en’)
== Parsing ‘/var/spool/asterisk/voicemail/context-name/extension/INBOX/msg0000.txt’: Found
== Parsing ‘/var/spool/asterisk/voicemail/context-name/extension/INBOX/msg0000.txt’: Found
== Parsing ‘/var/spool/asterisk/voicemail/context-name/extension/INBOX/msg0000.txt’: Found
– Executing [3903@iax2user:11] Playback(“SIP/extension-0b517558”, “vm-goodbye”) in new stack
– <SIP/extension-0b517558> Playing ‘vm-goodbye’ (language ‘en’)
– Executing [3903@iax2user:12] Hangup(“SIP/extension-0b517558”, “”) in new stack
== Spawn extension (iax2user, 3903, 12) exited non-zero on ‘SIP/extension-0b517558’

Anyone can tell me what’s the reason?

Thanks in advance.

Anyone can help?