If I connect outlook to port 465 with the same details, but for the mailbox, if I use IMAP, it won't send. If I use POP3 for the mailbox, it is able to send. And, I have postfix and dovecot installed in my mail server. What could possibly causing this? If I use thunderbird, it works. But not with Outlook when using IMAP for the mailbox. I am confused how sending mail is related to IMAP... I usually connect IMAP with port 993, and SSL is configured correctly, and I connect POP3 with 995.
The thing is, that everything goes well with IMAP. But it just doesn't seem to care about connecting to SMTP. Everything was fine until I changed my dovecot auth to use MySQL database instead of /etc/passwd.
EDIT:
I realized that Outlook doesn't even try to authenticate to the SMTPS server. Even if I enter the wrong password, Outlook just continues, no errors, and no access info in the logs. So, I think this must be a outlook problem. But I am still not so sure. I could create a test account, if anyone is able to test it, and see if they can reproduce the issue.
Another update:
I just saw that, even if I use the IP instead of the domain. It still won't work. And I am aware that many bots are trying to make unauthorized connection attempts to my SMTP server. Doesn't seem good right? So, I wish to hide some of my conf in these questions. Ask me, and I will post the conf. But please ask the particular conf which is needed.