Elastix Voicemail to Email not working

I was trying to configure my Elastix voicemail to send voicemail on Email. but the email was not being delivered to the my email address. I had configured properly my remote SMTP under mail configuration. I was able to send email from my elastix mail system and emails was being delivered to my email address.

But Voice mail was not being delivered to users email address.

I started troubleshooting I checked the log

tail -f /var/log/maillog

I found below error message

Apr 16 01:29:26 localhost postfix/qmgr[1820]: 6B600C90A91: from=<asterisk@pockw.localdomain>, size=813, nrcpt=1 (queue active)
Apr 16 01:29:49 localhost postfix/smtp[1937]: 6B600C90A91: to=<gkhanin@outlook.com>, relay=gkhan.in[173.254.220.66]:25, delay=23, delays=0.02/0.01/22/0.33, dsn=5.0.0, status=bounced (host gkhan.in[173.254.220.66] said: 550-Verification failed for <asterisk@pockw.localdomain> 550-The mail server could not deliver mail to asterisk@pockw.localdomain. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. 550 Sender verify failed (in reply to RCPT TO command))
Apr 16 01:29:49 localhost postfix/cleanup[1934]: 7537CC90A92: message-id=<20160415222949.7537CC90A92@pockw.localdomain>
Apr 16 01:29:49 localhost postfix/qmgr[1820]: 7537CC90A92: from=<>, size=3184, nrcpt=1 (queue active)
Apr 16 01:29:49 localhost postfix/bounce[1939]: 6B600C90A91: sender non-delivery notification: 7537CC90A92