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Voicemail is setup as after hour action for a In-Group; it is working fine but voicemail unavailable message is playing back with 3 to 4 seconds of delay.
Need your advice to remove this delay.

CLI logs.
[Apr 13 07:25:36] -- Executing [8557321158@trunkinbound:1] AGI("SIP/NPrimary-00000015", "agi-DID_route.agi") in new stack
[Apr 13 07:25:36] -- Launched AGI Script /var/lib/asterisk/agi-bin/agi-DID_route.agi
[Apr 13 07:25:36] -- <SIP/NPrimary-00000015>AGI Script agi-DID_route.agi completed, returning 0
[Apr 13 07:25:36] -- Executing [99909*223***DID@default:1] Answer("SIP/NPrimary-00000015", "") in new stack
[Apr 13 07:25:36] -- Executing [99909*223***DID@default:2] AGI("SIP/NPrimary-00000015", "agi-VDAD_ALL_inbound.agi") in new stack
[Apr 13 07:25:36] -- Launched AGI Script /var/lib/asterisk/agi-bin/agi-VDAD_ALL_inbound.agi
[Apr 13 07:25:36] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:36] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:37] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:37] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:38] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:38] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:38] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:38] -- Playing 'sip-silence' (escape_digits=) (sample_offset 0)
[Apr 13 07:25:38] -- <SIP/NPrimary-00000015>AGI Script agi-VDAD_ALL_inbound.agi completed, returning 0
[Apr 13 07:25:38] -- Executing [850266666666661000@default:1] Wait("SIP/NPrimary-00000015", "1") in new stack
[Apr 13 07:25:39] -- Executing [850266666666661000@default:2] VoiceMail("SIP/NPrimary-00000015", "1000,u") in new stack
[Apr 13 07:25:39] -- <SIP/NovaPrimary-00000015> Playing '/var/spool/asterisk/voicemail/default/1000/unavail.slin' (language 'en')

Thanks,
Zee
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VERSION: 2.12-541a BUILD: 160306-1053
Asterisk 1.8.23.0-vici, libpri-1.4.15 with DAHDI Version: 2.11
Dell R720 – No additional hardware.

please help!!!