Hi,
I've been playing around a lot lately with iredmail and I've successfully got it working.
However, I seem to have run into some problems. Whenever I use outlook to send emails out, my emails doesnt seem to reach my gmail account (no problems if i sent to my own personal domain). From the logs, I see that the email is successfully sent to google. Please refer below for the logs.

On the other hand, when i use the webmail (roundcube), the message is successful sent to my gmail account.

My outlook is currently configured to port 587 for SMTP.

Any idea what could be preventing the mail from reaching my gmail account whenever i use outlook?
I appreciate any inputs or suggestions. Thanks.

May 31 05:33:57 vmx9842 postfix/smtpd[14560]: connect from unknown[175.138.167.157]
May 31 05:34:00 vmx9842 postfix/smtpd[14560]: 2AA81120E2C: client=unknown[175.138.167.157], sasl_method=LOGIN, sasl_username=account@testing.com
May 31 05:34:01 vmx9842 postfix/cleanup[14574]: 2AA81120E2C: message-id=<005201cd3e9b$2a044bb0$7e0ce310$@tan@testing.com>
May 31 05:34:01 vmx9842 postfix/qmgr[12692]: 2AA81120E2C: from=<account@testing.com>, size=2697, nrcpt=1 (queue active)
May 31 05:34:02 vmx9842 postfix/smtpd[14582]: connect from localhost[127.0.0.1]
May 31 05:34:02 vmx9842 postfix/smtpd[14582]: 80F12120E2E: client=localhost[127.0.0.1]
May 31 05:34:02 vmx9842 postfix/cleanup[14574]: 80F12120E2E: message-id=<005201cd3e9b$2a044bb0$7e0ce310$@tan@testing.com>
May 31 05:34:02 vmx9842 postfix/qmgr[12692]: 80F12120E2E: from=<account@testing.com>, size=3644, nrcpt=1 (queue active)
May 31 05:34:02 vmx9842 postfix/smtpd[14582]: disconnect from localhost[127.0.0.1]
May 31 05:34:02 vmx9842 amavis[9781]: (09781-09) Passed CLEAN, MYUSERS LOCAL [175.138.167.157] [175.138.167.157] <account@testing.com> -> <xxxx@gmail.com>, Message-ID: <005201cd3e9b$2a044bb0$7e0ce310$@tan@techventurer.com>, mail_id: 6VSPryL5p-MX, Hits: -8.895, size: 2697, queued_as: 80F12120E2E, 1463 ms
May 31 05:34:02 vmx9842 postfix/smtp[14579]: 2AA81120E2C: to=<xxxx@gmail.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=2.7, delays=1.2/0.01/0/1.5, dsn=2.0.0, status=sent (250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 80F12120E2E)
May 31 05:34:02 vmx9842 postfix/qmgr[12692]: 2AA81120E2C: removed
May 31 05:34:03 vmx9842 postfix/smtpd[14560]: disconnect from unknown[175.138.167.157]
May 31 05:34:03 vmx9842 postfix/smtp[14583]: 80F12120E2E: to=<xxxx@gmail.com>, relay=gmail-smtp-in.l.google.com[74.125.127.27]:25, delay=1.5, delays=0.01/0.02/0.61/0.83, dsn=2.0.0, status=sent (250 2.0.0 OK 1338406442 to9si1178522pbc.98)